I plan on putting them on a 350 with 9.5 compression with the ZZ4 camshaft. Since these heads flow around as much as vette heads I figure I should get around 310HP. Would porting these heads give me another 20-30HP, enought to put the car into the lower 13's?

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92fb currently a TBI 305, (hold the laughter to a minimum). Going to be a 350 carb with 350HP and 400FT/Lbs.

 

I can't tell you what kind of horsepower gains to expect, but as far as porting them goes, dont' concentrate so much on the intake as on the exhaust. If you look at the exhaust flow numbers for these heads, they very low compared to Vette heads and Vortec heads. Especially since you're gonna put them on a 350, you're gonna need to get rid of more air and the exhaust flow on those heads is a good restriction.

Just my .02,

Jason

 

Pocket Porting, if done properly to any head, will give you 50-75 HP gain! That's just from personal experience!!

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1986 Trans AM
305 TPI
200,000+ miles (speedo/odometer non-funtional! Odometer reads 142,000)
4 Wheel Discs
9 bolt Borg Warner Rear (2.77's....oh joy) :P
Completely Stock
Soon to upgrade to a 355 converted from TPI to Carb, Edelbrock 750CFM Carb, Edelbrock Performer RPM Intake, Hedman Shorty Headers, Stock casting pocket ported heads (2.02/1.60 - 65cc), XE268 Cam, Moroso HEI ignition kit with external MSD Blaster II Coil and an MSD 6-AL Box!!
Current project: Keeping my 305 running until I get my income tax returns!

 

So paying attention to the exhaust side will yield better HP, huh. The Vette Heads have that D-shaped exhaust port, that's why they flow good on the exhaust? What is the definition of Pocket Porting is that cleaning up the CC and exhaust port?

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92fb currently a TBI 305, (hold the laughter to a minimum). Going to be a 350 carb with 350HP and 400FT/Lbs.

 

I forgot to say that I won't be porting my heads a guy that my dad works with will be porting them. I asked him to port and polish and he said he would recommend only porting not polishing because polishing gives up some torque and I didn't want that in a street car.

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92fb currently a TBI 305, (hold the laughter to a minimum). Going to be a 350 carb with 350HP and 400FT/Lbs.