New heads
Thread Starter
8th Gear
Joined: Jun 2004
Posts: 8
Likes: 0
From: patching Sussex
New heads
Hi, guys'
I'm from across the pond but still have the same problems. I've just had the heads changed on my 1980 L48 Vette and I seem to have a flat spot with the 'pedal to the metal' scenario. The car is factory standard except with an Edelbrock cam, Edelbrock heads a rebuilt Rochester and all the emissions gubbins removed and a pair of stainless steel pipes underneath.
The compression has gone up to 10:1 apparently but there is a definite pause when you floor the pedal. It then roars into life and everything is hunky dory.
My other question is just how much hp gain should I expect from the above mods. Factory standard was 190 so now where do I stand ?? I reckon about 275 ?????? It doesn't half sound good though. Grrrrrrrrr.
I'm from across the pond but still have the same problems. I've just had the heads changed on my 1980 L48 Vette and I seem to have a flat spot with the 'pedal to the metal' scenario. The car is factory standard except with an Edelbrock cam, Edelbrock heads a rebuilt Rochester and all the emissions gubbins removed and a pair of stainless steel pipes underneath.
The compression has gone up to 10:1 apparently but there is a definite pause when you floor the pedal. It then roars into life and everything is hunky dory.
My other question is just how much hp gain should I expect from the above mods. Factory standard was 190 so now where do I stand ?? I reckon about 275 ?????? It doesn't half sound good though. Grrrrrrrrr.
Drifting
Joined: Dec 2002
Posts: 1,861
Likes: 2
From: New Zealand
Re: New heads (deadlydecapod)
..........it might help to post the specs on the cam and heads (chamber size intake runner), trans & gearing.....
Is it a stock intake manifold and stock exhaust manifolds????????
275hp doesn't sound off the mark if it's a mild cam/heads........
Is it a stock intake manifold and stock exhaust manifolds????????
275hp doesn't sound off the mark if it's a mild cam/heads........
Thread Starter
8th Gear
Joined: Jun 2004
Posts: 8
Likes: 0
From: patching Sussex
Right, well I got back eventually. Cam is an Edelbrock performer, intake and exhaust manifolds are stock. Transmission is automatic and rear axle ratio is a tall one but I can't remember the ratio. Chamber volume is 64c.c on the RPM heads.
Does that help at all ?
The consensus over here is that the accelerator pump needs adjusting but if that is the case what figures do I take as relevant. Surely with the changes I've made the stock figures won't make sense.
Does that help at all ?
The consensus over here is that the accelerator pump needs adjusting but if that is the case what figures do I take as relevant. Surely with the changes I've made the stock figures won't make sense.
Safety Car
Joined: Aug 2000
Posts: 3,711
Likes: 43
From: San Antonio TX
Originally Posted by deadlydecapod
...Surely with the changes I've made the stock figures won't make sense.
About your flat spot...was it there before the modifications?
Drifting
Joined: Nov 2002
Posts: 1,665
Likes: 1
From: Ontario
One thing it could be, which is a quick thing to check, is your carb secondary airflap spring tension. If this spring tension is too low when you open the secondary throttle plates the engine will bog because of a sudden inrush of air.
Do a forum search the procedure has been posted numerous times.
Do a forum search the procedure has been posted numerous times.
Melting Slicks
Joined: May 2003
Posts: 2,253
Likes: 1
From: Rochester Kent
Welcome to the forum Tony, Who did the work for you and may I ask how much it cost you. I live in Kent and I am always toying with the idea of similar mods to my '81. Also post some pics of your car if you have any.
