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350 buildup
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Paul P
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Joined: 15 Aug 2002
Posts: 2403
Location: Townsend, Mass.
81574.74 points


1971 Chevrolet Chevelle

PostPosted: Thu Mar 08, 2012 4:33 pm    Post subject: Reply with quote

Something is wrong either it is running out of fuel or the exhaust is small.
What size header is on it?

I had those heads on a cast 10:1 piston 350.

It had a Weiand 7532 intake, 1 3/4" headers and a solid flat tappet 1st design off road "140" cam 257/269 .493/.512 112 lobe sep.

This was the first engine in my Chevelle. That motor turned 13 flat at 103mph. Weight with driver 3500lbs. I used to spin it a lot higher than 5400rpm. It was making about 400HP at the crank

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2001 Focus 2.0 Zetec
stock cams, bolt-ons and tune
15.63@87 MPH 1/4mi

1971 - Chevelle 408 SBC N/A
6.86@102.5 MPH 1/8mi
10.78@122 MPH 1/4mi
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af2
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Joined: 01 Sep 2003
Posts: 5558
Location: grassvalley, ca
71227.76 points


1933 Willys Coupe

PostPosted: Thu Mar 08, 2012 10:20 pm    Post subject: Reply with quote

harmon4127 wrote:
well ended getting 381tq @ 4400 and 355hp @5400. Tried 3 different spacers, jetting, timing 110 and 92 made no difference. Even tried a different carb. Gary said the motor is only flowing alittle over 500CFM.


What is the lash set at??
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harmon4127
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Joined: 05 Mar 2012
Posts: 24
Location: New richmond WI
919.72 points



PostPosted: Fri Mar 09, 2012 12:23 am    Post subject: Reply with quote

it's a hyd flat tappet i just tightened the rocker till i felt pushrod drag a bit then gave them all 1/4 turn. I have adjusted lots like this and never had a problem.
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squeeezer
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Joined: 02 Mar 2007
Posts: 2427
Location: new richmond WI
191524.76 points


1991 Chevrolet Camaro

PostPosted: Fri Mar 09, 2012 1:53 pm    Post subject: Reply with quote

thats much better
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af2
Member


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


1933 Willys Coupe

PostPosted: Fri Mar 09, 2012 3:32 pm    Post subject: Reply with quote

I would look at the valve springs. Sounds like the valve train is getting out of control. With that size cam I would have gone solid.
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Paul P
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Joined: 15 Aug 2002
Posts: 2403
Location: Townsend, Mass.
81574.74 points


1971 Chevrolet Chevelle

PostPosted: Fri Mar 09, 2012 5:32 pm    Post subject: Reply with quote

af2 wrote:
I would look at the valve springs. Sounds like the valve train is getting out of control. With that size cam I would have gone solid.


Good point something WONG WIT DAT

_________________
2001 Focus 2.0 Zetec
stock cams, bolt-ons and tune
15.63@87 MPH 1/4mi

1971 - Chevelle 408 SBC N/A
6.86@102.5 MPH 1/8mi
10.78@122 MPH 1/4mi
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harmon4127
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Joined: 05 Mar 2012
Posts: 24
Location: New richmond WI
919.72 points



PostPosted: Sat Mar 10, 2012 12:06 am    Post subject: Reply with quote

the valve springs are for .550 lift. I have no idea what's going on here. I know it should make 400hp. a few people have told me the intake runners are too big. I was told 190cc would have helped move more air. the motor is only flowing a little over 500CFM and i don't know why. I told bullitt cams my set up they made the cam accordingly.
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af2
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Joined: 01 Sep 2003
Posts: 5558
Location: grassvalley, ca
71227.76 points


1933 Willys Coupe

PostPosted: Sat Mar 10, 2012 12:41 am    Post subject: Reply with quote

The lift# on valve springs tell me nothing. Seat and open pressure tell me everything. I would not run less than 110# at the seat and around 275# open with a flat hydro.
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Paul P
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Joined: 15 Aug 2002
Posts: 2403
Location: Townsend, Mass.
81574.74 points


1971 Chevrolet Chevelle

PostPosted: Sat Mar 10, 2012 11:43 am    Post subject: Reply with quote

What header tube size are you running on this I'm not sure you stated that?

I agree with Adam 58cc out of those means that you milled a lot off of them. You could have a really bad port mismatch causing a lot of turbulence in the intake which would explain the 500cfm. If you can check what the port alignment I think you will find an issue there that you can fix.

There is a chance of an intake leak too if the intake is not flat to the head surface.

_________________
2001 Focus 2.0 Zetec
stock cams, bolt-ons and tune
15.63@87 MPH 1/4mi

1971 - Chevelle 408 SBC N/A
6.86@102.5 MPH 1/8mi
10.78@122 MPH 1/4mi
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squeeezer
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Joined: 02 Mar 2007
Posts: 2427
Location: new richmond WI
191524.76 points


1991 Chevrolet Camaro

PostPosted: Sat Mar 10, 2012 7:05 pm    Post subject: Reply with quote

Egt will show an intake leak
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harmon4127
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Location: New richmond WI
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PostPosted: Sun Mar 11, 2012 1:59 am    Post subject: Reply with quote

im not an engine guy how do i check seat pressure? and what am i looking for on port alignment
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Big Dave
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Joined: 04 Dec 2005
Posts: 2646
Location: Tampa Florida
119973.02 points



PostPosted: Sun Mar 11, 2012 2:31 pm    Post subject: Reply with quote

You need a valve spring checker (basically it is a spring scale combined with an arbor press) to know what you have now. Best bet, since valve springs are a consumable part of the car, is to buy a new set of springs to match the cam manufacturers recommendation.

Big Dave
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harmon4127
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Joined: 05 Mar 2012
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Location: New richmond WI
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PostPosted: Sun Mar 11, 2012 9:37 pm    Post subject: Reply with quote

I need a suggestion, i was debating sending the heads back or calling them cause there is something wrong here. I ordered the heads from skip white performance maybe there is something wrong with them. What to you guys think?
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af2
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Joined: 01 Sep 2003
Posts: 5558
Location: grassvalley, ca
71227.76 points


1933 Willys Coupe

PostPosted: Sun Mar 11, 2012 9:51 pm    Post subject: Reply with quote

harmon4127 wrote:
I need a suggestion, i was debating sending the heads back or calling them cause there is something wrong here. I ordered the heads from skip white performance maybe there is something wrong with them. What to you guys think?


Shyt!! I knew this was going to happen!!!!

The valve springs he has on his heads are not the best for a better word!
You have a Hydraulic flat tappet cam with .540" lift that will need premium springs period that he supplies for another$$.

You need a better spring and that is all.

Skip can and will help you out if you had the spring height available.

The standard 1.250 spring is not the one you want.
Hopefully the heads have a 1.5 spring cut.
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harmon4127
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Joined: 05 Mar 2012
Posts: 24
Location: New richmond WI
919.72 points



PostPosted: Sun Mar 11, 2012 11:25 pm    Post subject: Reply with quote

well it did not perform all that well with my previous cam either. That cam was only 480 480 lift with 231 231 duration with a 110 lobe sep. What is happening with these springs that i have now?
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