Home | Register | Login | Contact Us

 
Auto Math
Classifieds
Forum
Gallery
Games
Garage
Tech Articles
Utilites
 
FAQFAQ    SearchSearch    RegisterRegister    Log inLog in    Log in to check your private messagesLog in to check your private messages    Forum Subscriptions1/4 Mile Table 

Building a forged hi-comp 350, quench & dyn. comp questions

 
Post new topic   Reply to topic    SMOKEmUP.com Forum Index -> Chevy - Small Block Gen 1
View previous topic :: View next topic  
Author Message
Orlando71_C10
Newbie


Joined: 09 Apr 2012
Posts: 2
Location: Orlando, FL
229.64 points



PostPosted: Mon Apr 09, 2012 7:46 am    Post subject: Building a forged hi-comp 350, quench & dyn. comp questions Reply with quote

Hi everyone!

Been lurking (pre-research.. lol) on the forum for a little while now... Finally getting all the pieces together to build a forged std. bore 350.

I'm building this engine for my 1971 C10 step side (700r4 w/ 2500 stall, 3.73 gears, 3500lbs)it's going to be my weekend driver and occasion work truck too. I ride a motorcycle as my year round daily so I'm not too concerned with fuel consumption. I would like to run 93 octane.

First here's my engine list:

69' 010 (high nickel) std. bore 350, 4 bolt (non-decked w/ factory .025 piston depth)

67cc World Product heads 2.02 valves

GM forged 350 crank

original Thick I-beam "X" rods

TRW L2252A (L2252F) forged dome pistons (11cc or .220" dome)

Comp Cam Mutha Thumper 12-600-4 w/ 283 intake duration

This combo yields: Static compression - 11.25:1, Dynamic compression - 8.7:1
(w/ 0deg cam advance timing)

Quench depth of .067 w/ .042 gasket.

I realize my quench is too big, and if I go with a .015 gasket I can get it down to .040. However, I've also heard that with the big dome forged pistons I have I may want a little more quench depth.

1) Is this true? Will the dome pistons influence the quench depth desired? (I understand the quench depth isn't a measurement of the combustion chamber)

With the .015 gasket, I will raise my compressions up to: 12.14:1 Static and 9.36:1 Dynamic.
Unless I retard my cam timing to -4 and this will yield a Dynamic of 9.04:1

2) Is this still 93 octane friendly?

3) How much will retarding my cam timing to -4 deg influence my engine?

4) Or.... should I just find someone that has an equally good set of heads with 76cc to trade?

5) Or as a last resort possibly.... I even heard something about milling or even fly cutting my pistons down a little. (haven't researched this yet, and hesitant on cutting into them.)

BTW...Already bought the shortblock combo and the heads and really want that cam!

Any help would be greatly appreciated.

-Brent



IMG_0322-cropped.JPG
 Description:
My little C-10 needs some GRUNT!

Download
 Filename:  IMG_0322-cropped.JPG
 Filesize:  29.14 KB
 Downloaded:  633 Time(s)


_________________
There's no replacement for displacement... Except for BOOST!
Back to top
View user's profile Send private message
af2
Member


Joined: 01 Sep 2003
Posts: 5558
Location: grassvalley, ca
71227.76 points


1933 Willys Coupe

PostPosted: Mon Apr 09, 2012 7:37 pm    Post subject: Reply with quote

How did you come up with that Compression. Why do you want to run .067???

With the the heads I would want to be in the .040" range.

Look at a better cam also. Man Hot Rod sells a lot of Comp stuff.

That should be a solid dome which means you can mill it off if need be.

The dome has nothing to do with the squish unless you are running a Hemi.
Back to top
View user's profile Send private message
10sec.et
Member


Joined: 29 Mar 2006
Posts: 3473
Location: Houston,Texas
346658.74 points


1969 Oldsmobile Cutlass

PostPosted: Mon Apr 09, 2012 11:47 pm    Post subject: Reply with quote

i dont think he wants to run .067. thats what he will end up with, as i understand it, using what he has without making a lot of changes.

i would go with a better cam also. personally, i prefer custom grinds. they arent that much more expensive.

are those heads aluminum ? aluminum heads will be a big help keeping you on pump gas.

_________________
af2 wrote:
It seems we can look at our magical Balls and come up with a fix?

Back to top
View user's profile Send private message
af2
Member


Joined: 01 Sep 2003
Posts: 5558
Location: grassvalley, ca
71227.76 points


1933 Willys Coupe

PostPosted: Tue Apr 10, 2012 12:48 am    Post subject: Reply with quote

10sec.et wrote:
i dont think he wants to run .067. thats what he will end up with, as i understand it, using what he has without making a lot of changes.

i would go with a better cam also. personally, i prefer custom grinds. they arent that much more expensive.

are those heads aluminum ? aluminum heads will be a big help keeping you on pump gas.


Not knowing the heads the cam grinder will be throwing darts at the board guessing.

I will never buy a shelf cam after dealing with Mike Jones(east coast) and John D (40 miles from me) For $30 more on a flat solid and $80 more for a roller with the cast distributor gear compared to Comp you can't go wrong.
Back to top
View user's profile Send private message
squeeezer
Member


Joined: 02 Mar 2007
Posts: 2427
Location: new richmond WI
191524.76 points


1991 Chevrolet Camaro

PostPosted: Tue Apr 10, 2012 2:01 pm    Post subject: Reply with quote

Thoze cams leave way too much on the table!!!!!!!!!!
.040 + steel rods = true luv Laughing

_________________
Back to top
View user's profile Send private message
squeeezer
Member


Joined: 02 Mar 2007
Posts: 2427
Location: new richmond WI
191524.76 points


1991 Chevrolet Camaro

PostPosted: Tue Apr 10, 2012 2:04 pm    Post subject: Reply with quote

Xtra quench or squisher is for turbo/ supercharger doodz
Or aluminuminum rods
I dont know anyother practical application for xtra squish

_________________
Back to top
View user's profile Send private message
af2
Member


Joined: 01 Sep 2003
Posts: 5558
Location: grassvalley, ca
71227.76 points


1933 Willys Coupe

PostPosted: Tue Apr 10, 2012 9:49 pm    Post subject: Reply with quote

Those X rods are a joke from the past, period. I have had some X rods 25 or better lighter than a normal 350 rod. Like the dimple rod you have to weigh them.
Back to top
View user's profile Send private message
Orlando71_C10
Newbie


Joined: 09 Apr 2012
Posts: 2
Location: Orlando, FL
229.64 points



PostPosted: Wed Apr 11, 2012 3:19 am    Post subject: Reply with quote

After doing more research I'm thinking I'll probably just mill the pistons. I still need to inspect them to verify they are solid though and then mill the dome off flat. I'm currently working in Saudi Arabia and figured I'd decide what to do while sitting on my butt waiting for prayer times (5x/day).

When I calculate 0cc dome w/ .015 gasket and 0 deg timing, it puts my dynamic compression at 8.14:1 and quench at .040. According to the majority of what I have read over the past 3 days, this is optimum for a street/strip engine.

I'm not looking to spend alot on this build. I found out that this shortblock was know to run 11.5 @ about 115 in a 1st gen Camaro on pump gas that he drove to the track before I purchased it... I believe the only difference was he had 76cc heads.
Since this combo ran so well before... I'm feeling pretty confident in it's durability.... just worried about detonation more than anything.

I am curious why there is so much question over the Comp Mutha Thumper cam???

Thanks for the input,
Brent

_________________
There's no replacement for displacement... Except for BOOST!
Back to top
View user's profile Send private message
squeeezer
Member


Joined: 02 Mar 2007
Posts: 2427
Location: new richmond WI
191524.76 points


1991 Chevrolet Camaro

PostPosted: Wed Apr 11, 2012 12:18 pm    Post subject: Reply with quote

thumper series Q .......IF YOU ALREADY HAVE IT USE IT
but a custom grind will give you lost drivability,torque, or horsepower over that marketing stick
every situation needs its own cam
n20 different cam
supercharger another different cam
turbo another different cam
n/a u guessed it another different cam

so where does the thumper series fit in you ask?.................car shows and street rods

_________________
Back to top
View user's profile Send private message
10sec.et
Member


Joined: 29 Mar 2006
Posts: 3473
Location: Houston,Texas
346658.74 points


1969 Oldsmobile Cutlass

PostPosted: Sun Apr 15, 2012 2:33 am    Post subject: Reply with quote

squeeezer wrote:

so where does the thumper series fit in you ask?.................car shows and street rods


EXACTLY!!!!! the guys that buy those just like the sound. the only time those cars get close to a race track is when theres a show in the parking lot. LOTS of power left on the table just for the sake of sounding cool. but hey, ya can tell em its a 3/4 race cam and you will get lots of oos and aahs Rolling Eyes .

_________________
af2 wrote:
It seems we can look at our magical Balls and come up with a fix?

Back to top
View user's profile Send private message
af2
Member


Joined: 01 Sep 2003
Posts: 5558
Location: grassvalley, ca
71227.76 points


1933 Willys Coupe

PostPosted: Sun Apr 15, 2012 3:34 am    Post subject: Reply with quote

10sec.et wrote:
squeeezer wrote:

so where does the thumper series fit in you ask?.................car shows and street rods


EXACTLY!!!!! the guys that buy those just like the sound. the only time those cars get close to a race track is when theres a show in the parking lot. LOTS of power left on the table just for the sake of sounding cool. but hey, ya can tell em its a 3/4 race cam and you will get lots of oos and aahs Rolling Eyes .


Trying to think back I believe Crower had their Beast line of cams that sounded great to someone that don't know what a small block should sound like. And they were flat hydraulic to boot. I remember racing a guy that had one of those cams and claimed he shifted between 8 and 9 thousand. What a Joke. I shifted at 7800 with my solid Isky. and he was not even close. I told him to switch the Tach from 6 cylinder to 8 cylinder and never seen the car again.
Back to top
View user's profile Send private message
Display posts from previous:   
Post new topic   Reply to topic    SMOKEmUP.com Forum Index -> Chevy - Small Block Gen 1 All times are GMT - 5 Hours
Page 1 of 1

 
Jump to:  
You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot vote in polls in this forum
You cannot attach files in this forum
You can download files in this forum
Home | Contact Us | Automath | Cam Files | Dyno Search | Forum | Garage | Picture Gallery | Reaction Timer

Copyright 1997-2016 SMOKEmUP.com All rights reserved.
Advertising Info     Disclaimer     Privacy Policy