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Looking for suggestion on engine build
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96capriceMGR
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Joined: 23 Aug 2003
Posts: 814
Location: New London Wisconsin
20327.88 points


1996 Chevrolet Caprice

PostPosted: Mon Aug 07, 2006 10:10 pm    Post subject: Reply with quote

Dave, I wont advocate a LT1(gen2) motor unless someone wants injection which is not a topic here, the LT1 is not much more than a gen1 without the injection yeah there are cooling differences but the injection is a BIG part.

I just advocated the late gen1 blocks with roller cam provisions, the later rotating assemblies are great, one piece rear mains don't generally leak, less chance of finding an old thoroughly beat block with a hidden crack that halts the project.

I will build a motor oneday but for now the 100K shortblock serves me well, I cammed this shortblock at about 60-65K miles too so it aint like it has had an easy life. The newer stuff is just made better so why not take advantage of it?
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Wolf333
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Joined: 31 Jul 2006
Posts: 10
Location: Chicago, Illinois
383.14 points


1989 Pontiac Firebird

PostPosted: Mon Aug 07, 2006 10:11 pm    Post subject: Reply with quote

Wolf333 wrote:
Jeff, personally i would put the most work into the motor itself, yes balancing the motor will help, now if you want a cheap way to get more power, polish out the heads and port match the intake, it really wont cost anything except time, now as for the bigger cam, find out the std lift on it and dont go a to much higher (i.e. .054" to .056") is a pretty descent amount, you dont want a really big lift, im sure you already know this but it is possible to hit the valve on the piston, also to big of a lift will cause you to lose vacuum (power brakes) good luck with the camaro, sounds like a fun project.
Adam


my mistake i messed up, i meant to say .454" to .460"

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artinla
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Joined: 09 May 2006
Posts: 233

8558.30 points


1971 Chevrolet Nova

PostPosted: Tue Aug 08, 2006 12:38 am    Post subject: Reply with quote

96Caprice..

I had a Nova years ago with a 350 that had over 100K miles on it and the older and looser it got, the faster it went. It was a stock 300HP 350 with a Q-Jet and it would do nearly 100 in the quarter with an open rear end.

Sometimes engines defy all logic.

To stay on topic, I wanted to say that after re-reading all of the above, I might go with 1.6 rockers on that cam since you have to buy new ones anyway. The lift seems just a bit low to me assuming that you intend to replace the valve springs.

Art
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gen1camaro
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Joined: 05 Aug 2006
Posts: 14

855.88 points



PostPosted: Sat Aug 12, 2006 6:42 pm    Post subject: Reply with quote

Well the block, crank, rods-pistons, and oil pan are off to the machine shop now. Local old school crusty guy who is working out of an oversized garage. This guy was reccommended by just about everyone I have spoken with locally. My $2000 budget. Yeah, you might as well put it in the crapper and flush it. After talking with the engine builded we are pretty much on the same page. We are going with .030 flat top hypereutetic's, .010 crank grind, balanced crank,rod,pistons, (pro comp?) true roller timing chain with thrust washer and bearing, he prefers to put a stiffer relief spring in a stock oil pump which makes it not quite as high flow as a high volume. This guys first words were most people over cam and head a motor and waist money since the engine never runs right for the street. I am buying a set of new cast 180cc runner, 2.02-1.60 heads with all the goodies. screw in studs, guide plates, bronze bushings, 3angle grind, stainless valve, etc, etc,. He sells the heads for $825. Kind of pricy but he swears by them. I am stepping up and going full roller on the cam and rockers. He is going to look further into the cam specs and exact set up to use since the roller upgrade was a last minute choice. He is telling me that stall converters are a pain in the ass for a street driven car. Having never driven one I couldn't argue or agree. He swears that it is possible to get a good lumpy, lump idle with vacuum, and also plenty of horsepower. He is figuring with 72cc heads, and flat tops that I should be in or under 9.5:1. The nicest part is the guys shop is backed up a month and half so he is figuring around 2 months to get the parts ready to build. That will give me time to save for the added cost and put us into fall when the outdoor chores are over anyway. He insisted on me letting him install the cam, crank, and #1 piston so he can degree the camshaft? I have heard of this but not sure what it means. Plan to read up more on the subject. For those of you interested I will post more as the build goes. I definitely appreciate everybodies input and I don't think I wil regret spending the extra money once I get it paid off that is.. Just paid the fricking cards off too. Any input is welcome Jeff
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SMOKEmUP
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Joined: 30 May 2002
Posts: 3169

65097.54 points


1979 Chevrolet Camaro

PostPosted: Sat Aug 12, 2006 8:53 pm    Post subject: Reply with quote

If this guy is building your motor and telling you not to get a stall converter I wouldn't use him to build my motor. Any time you put in a performance camshaft the rpm range is raised higher. Raising the operating RPM will result in more power provided the supporting modifications are in place for the added airflow requirements. Now if you raise the RPM with an automatic transmission it takes time to get the motor into the RPM range where it makes power. Using a higher stall torque converter the engine will flash right into the engines sweet spot. In short one of the best mods you can do for any automatic car is a stall converter. I dropped 0.5 seconds in the quarter mile adding converter to my stock 2002 camaro Z28. Driveability and gas mileage will suffer but acceleration will increase.

What exact heads is he selling you? GM or aftermarket? Get us the details.

Pick a camshaft which meets your goals for the car.

Rough camshaft guide for a 350 chevy.

Stock cam around 200 degrees or less @ 0.05".
Towing cam 200 - 215 @ 0.05"
Mild performance 215 - 225 @ 0.05"
Performance 225 - 235 @ 0.05"
Race above 235 @ 0.05"

In building the motor you should select the cam shaft which meets your needs. If you are looking for a weekend warrior type car that will run good on the track and driven sparingly run around town 230 degrees intake duration is a good choice. If you're looking for a good all around performance cam I'd stay around 224 degrees intake duration.

Once you have selected the camshaft you plan to run find out the IVC, intake valve closing point at advertised duration, (not 0.05" IVC). This number will be used to determine the engines DCR or dynamic compression ratio.

Target a DCR of around 8.0:1 with iron heads and 8.5:1 with aluminum heads depending on where you live (average air temperature). If you live where it's really hot take a 1/4 of point off those numbers.

Now select the cylinder head chamber volume and quench height up on the engine so the DCR works out as planned. Target a quench height of 0.045".

For example: Using the DCR calc on the site. I had to play around with the cylinder head chamber volume to get the numbers I wanted. I used an average deck height for a small block chevy of 0.025" and selected a steel shim head gasket which has a 0.015" compressed height. The result is 0.040" quench height (This is a bit on the tight side.)

The cam I picked is comp cams CS 270AH-10,
Degrees Duration @ .050 Int./Exh. 224 / 230
Degrees Advertised Duration Int./Exh. 270 / 280
Gross Lift Int./Exh. 0.47 / 0.46
Lobe Sep 110
Int Center Line 106
IVC 61

Entering this into the DCR Calc .
Bore 4.03 (inches)
Stroke 3.48 (inches)
Rod Length 5.7 (inches)
Cyl. Head Vol. 69 (cc)
Deck Height 0.025 (inches)
Head Gasket Bore 4.1 (inches)
Head Gasket Thickness 0.015 (inches)
Piston to Cyl. Wall Clearance 0.003 (inches)
Top Ring Land Height 0.25 (inches)
Piston Dome Vol. -6.2 (cc)

Compression Ratio:
9.689 : 1

DCR @ 61 degrees ABDC
7.967 : 1
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96capriceMGR
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Joined: 23 Aug 2003
Posts: 814
Location: New London Wisconsin
20327.88 points


1996 Chevrolet Caprice

PostPosted: Sat Aug 12, 2006 9:31 pm    Post subject: Reply with quote

Sounds to me like the guy did his learning DECADES ago and has stopped learning since. Sad

Smokem makes a good point on the stall I run a 3400 in a daily driver I occassionally tow with, it is not some POS B&M or the like though.
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artinla
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Joined: 09 May 2006
Posts: 233

8558.30 points


1971 Chevrolet Nova

PostPosted: Sun Aug 13, 2006 2:34 am    Post subject: Reply with quote

This guy might know machine work, but he doesn't know much about building an engine. Do NOT just let him throw a cam in there and some stock type heads. If you go with 180cc, they damn well better be good ones. 180 is what I would consider the lower limit for any performance beyond bone stock. I would consider 190 or 200cc for your application.

He is probably suggesting the S/R torquer heads. I think it is a waste of money because the Sportsman II's cost only slightly more.

On the cam, just come here and get your cam suggestions. Ask the guy what your dynamic compression ratio will be, and come here and tell us his reply. My money says he won't know. Also, he should be able to tell you your deck height and exactly what the chamber volume of the heads will be. We even need to know exactly what head gasket he will use, because it is critical in calculating your static compression and quench. And like Smomemup said, 9.5 to 1 doesn't mean squat if your dynamic c/r is too high.. you won't be able to run pump gas. If it is too low, power will suffer greatly.

If he recommends no stall converter, he is building you a stock motor. If not, then he is a fool for not using the proper stall.

Buy your own parts, know what you want in machine work and double check the machinist's work when he is finished. Otherwise this guy is going to take your money and you won't be happy with the engine.

Art
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gen1camaro
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Joined: 05 Aug 2006
Posts: 14

855.88 points



PostPosted: Sun Aug 13, 2006 5:48 am    Post subject: Reply with quote

Now that is why I come here for the input. I will call him beginning of this week and get some specifics. I am wondering if because I told him that I want a streetable pump gas motor that he may be greatly downsizing my build. I have to say the heads that he showed me were heavier than hell compared to the stock cast heads off the 327. The ports and passaged looked absolutely huge. All of the reading I have done so far suggest that the 180cc runners are about right for 355cu in. they suggest more cu in for the larger runners? Keep in my mind I am a newbie so I am at the mercy of the research info. He seemed to think the motor he has planned will reach numbers toward 450hp without a stall and my common sense tells me that is not reasonable. The runners and ports were absolutely frickin huge compared to the 327 heads that I had on there. I will get more specifics from him. I do want radical but also reliable and streetable. Afterall the wife needs to drive this home from the parties when I have a little too much fun. I appreciate the heads up from all of you. Will get some specific info and be back this week for more on the dcr. JEff
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96capriceMGR
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Joined: 23 Aug 2003
Posts: 814
Location: New London Wisconsin
20327.88 points


1996 Chevrolet Caprice

PostPosted: Sun Aug 13, 2006 6:30 am    Post subject: Reply with quote

My motor is over 450fwhp but probably under 500fwhp the heads are opened up to 190cc and flow 203cfm at .300 which is what they did stock at .500 Shocked peak at 275cfm at .600, I am not running that much lift though, valves are little 2.00/1.56. 11.5:1 compression which you wont get away with carburated, and a cam mid 220s on the intake with mid .500s lift. The LT1 intake also boosts HP at the expense of some low and midrange torque, not that mine drives bad but your carbed motor with similar cam and headflow would make less HP and more average torque due to the intake.

I post this for comparison as to what it takes to get 450fwhp vs. what he is giving you. My LT1 has some definete differences from Gen1 motors but has a whole lot more in common with them, heads and intakes are routinely modified to be swapped between the two that is how similar.

This setup drives just fine today I will put 250miles on it I have 3400 stall and 3.73 gears though the lockup torque converter and OD tranny tame that though.

I know I don't shutup about the LT1 but once you look at it closely a lot of the info is useful when building a gen 1 because the LT1 is a gen 1 with a little different cooling and distributor.
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Big Dave
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Joined: 04 Dec 2005
Posts: 2646
Location: Tampa Florida
119973.02 points



PostPosted: Sun Aug 13, 2006 8:23 am    Post subject: Reply with quote

I agree with those who espouse that you need either a manual transmission or a loose converter to run a high performance (long duration, or one with a very narrow LSA) cam. If your converter is too tight for the cam it will actually die when you put it in gear. That is why they call it stall, because if it is too tight it stalls the motor.

There is one difference in the stall convert that I run on the street and I think Smokemup and 96CapriceMGR and 87Calais use that didn't come up in conversation. That is they are all in front of a modern overdrive tranny with the ability to lock-up the converter so that it doesn't slip at all on the road when driving. I believe you mentioned you were using a TH350.

A loose converter generates more heat than the stock stall speed converter. The looser it is, the more heat it generates. once the fluid gets above 270F it starts to oxidize and break down. Since the normal operating temp is in the 210 to 240 F range it doesn't take much to push it over the edge. For that reason a really big cooler is required for a very loose converter. I have installed the biggest transmission cooler sold for my 3400 converter that I also run on the road daily.

http://s45.photobucket.com/albums/f63/3454545/?action=view&current=DSC00888.jpg&refPage=&imgAnch=imgAnch1

With a loose converter that locks up you get great performance without any of the heating issues and enjoy "reasonable" (how reasonable can a 582cid with 4.56 gears be?) gas mileage. That is another reason to put a 200R4, 700R4, or the new Allison A6 six speed OD tranny on your wish list.

If you get a computer to control everything you can use EFI like 96CapriceMGR and Smokemup have discovered make gobs of streetable power and then use the 4L60 (65E), or when your motor gets big enough the 4L80E.

Big Dave
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SMOKEmUP
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Joined: 30 May 2002
Posts: 3169

65097.54 points


1979 Chevrolet Camaro

PostPosted: Sun Aug 13, 2006 8:54 am    Post subject: Reply with quote

Big Dave brings up a good point that I thought of but didn't want to address in my post. An overdrive transmission with a lock up converter is the way to go. You can run a high stall and still be streetable. A lot of the LS1 crowd run 3600 stall converter on stock engine and get away with it.

Since you're running a turbo 350 you have to be more reasonable with the converter selection since it doesn't have lockup. Cam choice and driving style will determine the proper converter, and like everything else it will be a compromise. I ran a non lockup 3000 rpm converter in my 79 camaro when it had a turbo 350. Yes drivabilty suffered and I feel that's about the biggest you should go in a non-lockup transmission for any vehicle that sees street duty regularly.

Talk to this guy and ask him questions and get details on the engine build. Know what you're getting and measure everything yourself, cc the heads (don't just believe what the manufacturer states), get head gasket information, measure the deck height, and measure piston relief volume. Know exactly what the compression ratio and DCR work out to yourself. After doing this WRITE IT DOWN. You'll be surprised how many times you'll forget and refer back to it.
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artinla
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Joined: 09 May 2006
Posts: 233

8558.30 points


1971 Chevrolet Nova

PostPosted: Sun Aug 13, 2006 3:56 pm    Post subject: Reply with quote

Dave.. That was one fine looking post. I love the way you accentuated the finer points and names with the bold face print. Much thought and a little flair went into that layout.

I applaud your creativity. I bet your sock drawer is in perfect order! Laughing

J/K all good points just wanted to rag on you because I am bored and retarded all at the same time.


Gen1: Smoke and Dave are both giving you great advice. I agree that 3000 is the very highest stall you should consider. As for the 180CC intake runners, they can work fine but will limit you to around 6000-6200 usable rpm, and that is assuming that you choose the perfect cam based on your gearing, stall, C/R, etc. Trust that choice to the guys here and you won't go wrong. This forum has saved it's members THOUSANDS of dollars by avoiding the mistakes of others. I wish I could have had the advice of these guys when I first started building engines.. I could have saved a fortune and probably at least one wife!

Art
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af2
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Posts: 5558
Location: grassvalley, ca
71227.76 points


1933 Willys Coupe

PostPosted: Sun Aug 13, 2006 5:15 pm    Post subject: Reply with quote

I worry about the heads! A lot of guys are taking the 305 heads and putting 2.02/1.6 valves in them and pawn them off as high performance. The fact is( after many years of research) they are crap! There is so much more to a head than I never thought about until I got back in the game. Mid lift flow is the most important part of the puzzle in a dual purpose car. The chamber shape I feel is the most important part of the combustion proses along with fast runners! ( which is always on the small side in a street motor)
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gen1camaro
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PostPosted: Sun Aug 13, 2006 10:58 pm    Post subject: Reply with quote

Subject: suggestions for gen1 engine build-up
I have always had my best results with word of mouth for services. This machinist comes highly reccommended by several people within my peer group, few of them whom are crusty old street rodder guys. My biggest problem is that I know enough to be dangerous, but I don't know enough to be able to have the confidence that I am getting what I want from this guy. As far as reputable I have no worries that what he is selling is all good stuff. His work comes highly reccommended and he is one of the few guys other than this forum who have gone out their way to explain things when I have questions. I do remember him saying that the 180 cc intake runnners on the head were desirable because the heads had constant good flow even in the low rpm range so without a stall converter (which I think I am going to change) the engine would make good power from off idle to about 5500rpms is what he is talking. If I can build something reliable that is for mostly street drving and can get even close to 400hp I would be smiles from ear to ear. Even with the worn out 327 all of maybe 275hp would melt the tire (open rear-end) from a stand still. I did find out that my transmission is actually a TH400 instead of the TH350 that I had thought. (once again shows my lack of knowledge on this stuff). The guy I bought the shortblock 350 from explained to me the differences in trans pan shape to tell the difference. I am pretty set against going with an overdrive automatic. Maybe way off in the future I may switch the car over to a tremtec or muncie manual. I may save that for my next build up when junior get closer to the teen years. I am planning on keeping the car stock appearing other than the 17" wheels and low pro's. Not to be stupid but wouldn't a tighter stall converter be called for in my application where I could use the stall for getting up the rpms some but want more stall lock up for street driving. Say 2000rpm stall? Hell I don't even know if they make a 2000 stall. I know that I am suffering from wanting the best of both worlds between hp and streetable. I just have to be able to whip my older brothers butt in his 68 firebird 400 and I would be plenty content. I do plan to get more info from the machinist on tuesday so hopefully I will at least know specifcs on the heads and deck height. I believe the head gaskets were just regular fel pro ones that come in the rebuilders gasket kit. Should I use others? I do also know that the builder is constantly refering to people overbuilding the motors and they never run good on pump gas. So pump gas is definitely one of the factors for the build. Thanks again guys. Jeff
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10sec.et
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Posts: 3473
Location: Houston,Texas
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1969 Oldsmobile Cutlass

PostPosted: Sun Aug 13, 2006 11:25 pm    Post subject: Reply with quote

B&M makes a 2000rpm converter. i would use whatever head gaskets the engine builder specifies. if the heads have been milled or the block decked you may run into problems using head gaskets of different thickness.
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