Re: Head porting questions

[bwallace]

I am currently having a pair of stock heads ported and my mechanic was looking for some information that I was unable to find after a number of hours of searching. Here is a list of questions he had:

Limit on Cam size with stock pistons, pushrods etc (Lift/Duration.
What's the largest valve size intake/exhaust anyone have used with stock heads?
Cam replacements suggestions.


Although he has over 15 years of experience porting heads and feels comfortable doing these heads, he has never ported a set of Buick V6 heads and wanted any information on common problems when porting these heads, he thinks he can get 2.0 intake and 1.5 exhaust. I bought this car from him bone stock and this is a project we are completing together, since I am no mechanic. I was also wondering should I hold off on replacing the cam and go with turbo and injector upgrades first. Any opinions welcome.

 

[Trbobuick]

bwallace-

Im sure your head potrter is awsome BUT, a guy that is used to porting chevy and ford heads will try and port these buicks like a chevy or ford head. The results are never pretty. Send them to a champion, cotton, chapman, duttwieler, or any other reputable buick vendor before your heads are wrecked.

 

[bwallace]

That was my concern, although I didn't pay a lot for the heads and bought them with this in mind, but do you have any idea's or information that make these heads so much different to port. He's a good friend and don't want to piss him off to much since I don't have the experience he has but I would like to steer him away from any trouble spots. He did cut up an old head into piece to see what he was working with so hopefully this will give him some insight. He hasn't started any porting yet he sent them out to be flowed to see what kind of numbers were looking at.

 

[blackbuick87]

Ben just make sure he stays conservative on his porting.
Stay away from the bigger valves, if he doesnt do it right the heads will crack in between the valves.

UNGN had a couple good posts about headporting, and what areas to open up. Do a search and give that to the guy. Pocket porting is pocket porting regardless of head as long as you keep it simple and dont try to make them a set of race heads

 

[The Radius Kid]

GNTTYPE.org has a really good headporting section there.
As to valves,I think you'll find that 1.77 intake and 1.50 exhuast is a bout as large as you can fit in thee without screwing everything up.
Flow should check in at ~165 cfm intake and ~105 exhaust.
Hope that helps a bit.

 

[ANS PETE]

We have done some heads with 1.830 in 1.550 ex valves.But this requires moving the intake valve guide over about .060.We have made 715 hp with this combo.But normally we run the 1.77 in 1.50 ex combo and have made 692 hp with this set up.I feel its not worth the time & expense to go with the bigger valves.We like to concentrate on the exhaust side to help spool up and to scavage the cylinder.Hope this helps, any other questions please ask. Pete

 

[bwallace]

Thanks everyone for the info. great information. I will keep you all posted once I have them finished and flowed.

 

[bwallace]

What is the CC for the stock heads I don't want to change the compression after porting.