| FAQ |
| Members List |
| Social Groups |
| Calendar |
| Search |
| Today's Posts |
|
#1
08-19-2023, 07:50 PM
|
||||
|
||||
Venolia domed piston info
Friend just picked up a 64 GTO with a 72 455, 7L4 heads, unknown HFT cam. It ran ok but he is going through the whole car. We pulled the heads off today and found the pistons were dome type Venolia. Only part number visible was 400B. Dome sticks up about .100 from deck. Obviously dome was picked to raise compression on the 7L4 heads. The plan was to put a set of #96 heads on and new cam, then seal it up for a quick, budget upgrade. First question, anyone know the dome cc on these? Venolia is out of business so I cannot find info online so far. Second question, any worry about clearance with #96 head? Once I know dome cc, I can calculate compression ratio of course.
__________________
1970 GTO 400 Atoll Blue, PS, PDB, A/C Was M20 4 speed, now has Keisler RS600 5 speed. |
|
#2
08-19-2023, 08:09 PM
|
||||
|
||||
|
I had a set of those that originally came with my engine (basket case). I never cc'd them but they did ping with 114cc heads (6H) with premium fuel. I had a machine shop mill the domes off and glass bead the tops of the pistons to run with 6x-8 heads at around 9.3:1.
__________________
Triple Black 1971 GTO |
|
#3
08-19-2023, 09:47 PM
|
||||
|
||||
|
Thanks. I know domes are problematic and can cause detonation even with big chambers. He may have to suck it up and go through the whole motor.
__________________
1970 GTO 400 Atoll Blue, PS, PDB, A/C Was M20 4 speed, now has Keisler RS600 5 speed. |
|
#4
08-20-2023, 07:21 AM
|
||||
|
||||
|
A 1/10” dome will not be a problem in terms of clearance, but with the 96 to 98 CC volume of those 1971 heads compression will be a problem.
Since you need to find out the CC volume just oil up the piston top. Pack clay on it to form the dome shape, then peel it off and CC that. You should easily be within 2 CCs of being correct which will then mean being well within 1/4 point of knowing the actual compression.. It’s very strange to me that someone would spend the money on custom pistons only to plop on a set of crap heads that do not have a full length divider in those center exh ports , which I believe is the way those heads are?
__________________
Wernher Von Braun warned before his retirement from NASA back in 1972, that the next world war would be against the ETs! And he was not talking about 1/8 or 1/4 mile ETs! 1) 1940s 100% silver 4 cup tea server set. Two dry rotted 14 x 10 Micky Thompson slicks. 1) un-mailed in gift coupon from a 1972 box of corn flakes. Two pairs of brown leather flip flops, never seen more then 2 mph. Education is what your left with once you forget things! Last edited by steve25; 08-20-2023 at 07:30 AM. |
|
#5
08-21-2023, 10:24 AM
|
||||
|
||||
|
See if there is a job number engraved on the bottom you can call Venolia about
__________________
Skip Fix 1978 Trans Am original owner 10.99 @ 124 pump gas 455 E heads, NO Bird ever! 1981 Black SE Trans Am stockish 6X 400ci, turbo 301 on a stand 1965 GTO 4 barrel 3 speed project 2004 GTO Pulse Red stock motor computer tune 13.43@103.4 1964 Impala SS 409/470ci 600 HP stroker project 1979 Camaro IAII Edelbrock head 500" 695 HP 10.33@132 3595lbs |
|
#6
08-21-2023, 10:32 AM
|
||||
|
||||
|
Quote:
__________________
1970 GTO 400 Atoll Blue, PS, PDB, A/C Was M20 4 speed, now has Keisler RS600 5 speed. |
| The Following User Says Thank You to pontiacmark For This Useful Post: | ||
|
#7
08-21-2023, 10:35 AM
|
||||
|
||||
|
Quote:
__________________
1970 GTO 400 Atoll Blue, PS, PDB, A/C Was M20 4 speed, now has Keisler RS600 5 speed. Last edited by pontiacmark; 08-21-2023 at 10:40 AM. Reason: Typo |
|
#8
08-21-2023, 01:43 PM
|
||||
|
||||
|
Man I just called them a few years ago about a set!
__________________
Skip Fix 1978 Trans Am original owner 10.99 @ 124 pump gas 455 E heads, NO Bird ever! 1981 Black SE Trans Am stockish 6X 400ci, turbo 301 on a stand 1965 GTO 4 barrel 3 speed project 2004 GTO Pulse Red stock motor computer tune 13.43@103.4 1964 Impala SS 409/470ci 600 HP stroker project 1979 Camaro IAII Edelbrock head 500" 695 HP 10.33@132 3595lbs |
|
#9
08-21-2023, 04:28 PM
|
||||
|
||||
|
Miled off the domes with no rebalance. Machinist assured me the slight overbalance condition wouldn't hurt in torquey motor. He shaved and glass beaded the piston tops and lightly honed to block keeping the side clearance in tolerance. I spent the re-balancing money on other stuff I needed and never regretted it. Ran it that way (with 4:56 gearset) for 10 years so it obviously got wound pretty tight all the time.
__________________
Triple Black 1971 GTO |
| The Following User Says Thank You to NeighborsComplaint For This Useful Post: | ||
|
#10
08-21-2023, 04:31 PM
|
||||
|
||||
|
A slight over balance does not harm anything, but a under balance can.
Mill ‘em, run em!
__________________
Wernher Von Braun warned before his retirement from NASA back in 1972, that the next world war would be against the ETs! And he was not talking about 1/8 or 1/4 mile ETs! 1) 1940s 100% silver 4 cup tea server set. Two dry rotted 14 x 10 Micky Thompson slicks. 1) un-mailed in gift coupon from a 1972 box of corn flakes. Two pairs of brown leather flip flops, never seen more then 2 mph. Education is what your left with once you forget things! |
| The Following User Says Thank You to steve25 For This Useful Post: | ||
|
#11
08-22-2023, 04:06 PM
|
||||
|
||||
|
Following this thread.
__________________
Brentwood, TN 69 & 70 GTO's |
| Reply |
|
|
The PY Online Forums is the largest online gathering of Pontiac enthusiasts anywhere in the world. Founded in 1991, it was also the first online forum for people to gather and talk about their Pontiacs. Since then, it has become the mecca of Pontiac technical data and knowledge that no other place can surpass.
Linear Mode
