Matchporting heads/intake
Team Owner
Joined: Jul 1999
Posts: 65,492
Likes: 230
From: Orange Park Florida
On an out and out drag race engine, it's worth maybe 20-40 hp from what I hear....but for a normal street car turning less than 5k rpm most all it's life....waste of time.....I have done it, and reworked other areas too, but found no significant differance for street driving....
Race Director
Joined: Dec 1999
Posts: 19,610
Likes: 778
From: Forked River NJ
Thread Starter
Racer
Joined: Oct 2004
Posts: 285
Likes: 0
From: Stockholm
If I can get 5hp it's worth it, can I get 20hp so much better.
I just finished the porting, I took the Fel Pro 1205 as a reference.
Not much to remove from the heads, more to remove from the RPM intake instead.
I just finished the porting, I took the Fel Pro 1205 as a reference.
Not much to remove from the heads, more to remove from the RPM intake instead.
Le Mans Master
Joined: Oct 2004
Posts: 5,269
Likes: 54
From: Orlando Florida
St. Jude Donor '05
Does your intake fit with the stock size gasket ?
I had to get a thicker (.120") gasket to get the bolt holes and the ports lined up correctly. With the stock (.060") gasket there was almost no gap at the bottom of the intake. If I had used the stock rubber strips and the .060" gasket the rubber strips would have been too thick and would have prevented the intake to go down far enough to compress the gaskets between heads and intake.
I installed the heads with the old used head gaskets (.038" thick), then set the intake down without any gaskets to see whe it makes contact first, at the bottom or at the head surfaces. I then placed .060" shims between intake and heads to simulate the gasket. The bolt holes didn't line up. I then used a .120" shim and voila... perfect ....
I used silicone (gasket maker) instead of the rubber strips, that way the intake gaskets compress to whatever they need to be and the silicone squeezes to whatever thickness without streesing the intake.
I believe if you use rubber or cork strips that are too thick you can crack the intake when tightening the bolts....
I had to get a thicker (.120") gasket to get the bolt holes and the ports lined up correctly. With the stock (.060") gasket there was almost no gap at the bottom of the intake. If I had used the stock rubber strips and the .060" gasket the rubber strips would have been too thick and would have prevented the intake to go down far enough to compress the gaskets between heads and intake.
I installed the heads with the old used head gaskets (.038" thick), then set the intake down without any gaskets to see whe it makes contact first, at the bottom or at the head surfaces. I then placed .060" shims between intake and heads to simulate the gasket. The bolt holes didn't line up. I then used a .120" shim and voila... perfect ....
I used silicone (gasket maker) instead of the rubber strips, that way the intake gaskets compress to whatever they need to be and the silicone squeezes to whatever thickness without streesing the intake.
I believe if you use rubber or cork strips that are too thick you can crack the intake when tightening the bolts....
Thread Starter
Racer
Joined: Oct 2004
Posts: 285
Likes: 0
From: Stockholm
Can't check right now.
Old engine is on the stand, waiting to be released from parts I will reuse.
It will be a suprise later on, but with my "luck" I think I will end up like you (or worse).
Here's my "shop".
Everything must happen in the small "free" area in front of the stand/workbench.
Old engine is on the stand, waiting to be released from parts I will reuse.
It will be a suprise later on, but with my "luck" I think I will end up like you (or worse).
Here's my "shop".
Everything must happen in the small "free" area in front of the stand/workbench.
Last edited by gbak; Apr 1, 2007 at 10:54 AM.
Melting Slicks
Joined: Feb 2006
Posts: 3,428
Likes: 5
From: Japan
Porting will definitely help your HP numbers, but you will only see the gain in the upper end of the RPM range. Also, remember that the manifold porting should result in holes that are slightly SMALLER than those in the heads. If they're exactly the same you'll have problems if you encounter any mismatch when bolting the intake down (which is likely).
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