71 BB, Oval vs Rect setup
Thread Starter
Burning Brakes
Joined: Mar 2004
Posts: 923
Likes: 4
From: Austin Tx
71 BB, Oval vs Rect setup
My bb 71 that I just bought came with 65 425 heads, LS6 intake, and Qjet on an adapter plate. Car runs great. But I've sold the heads to a C2 guy for nice money, and I was going to go with some edelbrock 100cc oval heads and put a 69 L36 intake with qjet and toss the adapter plate in the trash. But after driving the car a few times, I really like the feel of the rect heads and intake. Different from my 69 L36, not as snappy off the line, but more power overall. I would like to keep the engine compart stock, ie dual snorkel air cleaner. Should I get some edelbrock rect port heads and keep the intake and adapter plate, or am I hurting perf with the adapter plate. Is their an intake out there that is rect port but spreadbore for my qjet?
Race Director
Joined: Jan 2000
Posts: 13,014
Likes: 2,257
From: Corsicana, Tx
2020 C2 of the Year - Modified Winner
2020 Corvette of the Year (performance mods)
C2 of Year Winner (performance mods) 2019
2017 C2 of Year Finalist
Not sure what hood you have..but there are Q-jet edelbrock Performers, and Performer RPM intakes as well as Weiand Action plus series.
The Edelbrock 100 cc heads are sort of a cross between the two..oval and rectangular. You could easily open the ends of head ports to match your intake..wouldn't take too long. Out of the box, they will likely outflow your rectangular ports and will have much better response. A little cleanup work helps too.
I think the new Brodix Race Rite heads are a better deal. They also bolt right on..no issues and either the oval or rectangular both flow in the 340+ cfm range. That's a LONG way from your stock castings with port size of either 270 cc or 294 cc. Your stock ones are like 315/325 cc (short/long ports).
You could also look at the 305 CC AFR's....but ex ports are slightly raised on them.
You can order the Brodix milled too..maybe not to 100cc..but you can get close..just use thin gaskets with them. I think it's the best one out there for what you're looking for.
JIM
The Edelbrock 100 cc heads are sort of a cross between the two..oval and rectangular. You could easily open the ends of head ports to match your intake..wouldn't take too long. Out of the box, they will likely outflow your rectangular ports and will have much better response. A little cleanup work helps too.
I think the new Brodix Race Rite heads are a better deal. They also bolt right on..no issues and either the oval or rectangular both flow in the 340+ cfm range. That's a LONG way from your stock castings with port size of either 270 cc or 294 cc. Your stock ones are like 315/325 cc (short/long ports).
You could also look at the 305 CC AFR's....but ex ports are slightly raised on them.
You can order the Brodix milled too..maybe not to 100cc..but you can get close..just use thin gaskets with them. I think it's the best one out there for what you're looking for.
JIM
Melting Slicks
Joined: Mar 2005
Posts: 2,838
Likes: 10
From: Austin TX
Square ports with a Q-Jet?,..interesting.
What size BB are you running? Which O-port heads and which Square port heads are you considering?
What tranny and gears out back?
Also, I'd be surprised if anybody makes a square port intake with a spreadbore carb mount,..but I'm too old to be shocked by anything.
What size BB are you running? Which O-port heads and which Square port heads are you considering?
What tranny and gears out back?
Also, I'd be surprised if anybody makes a square port intake with a spreadbore carb mount,..but I'm too old to be shocked by anything.
Le Mans Master
Joined: Sep 2001
Posts: 7,739
Likes: 630
From: Unreconstructed, South Carolina
Nice new Bowtie Alum BBC heads F/S here ... appear same as rect Edelbrock RPM.
http://forums.corvetteforum.com/show...ighlight=heads
http://forums.corvetteforum.com/show...ighlight=heads
Thread Starter
Burning Brakes
Joined: Mar 2004
Posts: 923
Likes: 4
From: Austin Tx
Don't know if tranny is M20 or M21, need to get under there and look at the numbers. Rear end is 3.36. I was considering Edelbrock 100cc heads, or something else. I thought the qjet on a rect port was interesting as well.
