Epoxy modified GM BB intake ? (rect to rect-oval)
Thread Starter
Safety Car
Joined: Mar 2002
Posts: 3,780
Likes: 442
From: Southwest MI
Epoxy modified GM BB intake ? (rect to rect-oval)
I picked up a COPO 427 intake this weekend…. cheap, so I couldn’t pass it up :-). It has been modified to work with the new 502 Chevy heads. The guy had filled the top 20%, or so, of the intake ports with epoxy to match the height of the Edelbrock/GM rect-oval heads. Looks like a really nice job, epoxy is about 2” into the top of the runners, blended /contoured very nicely.
Anyone ever do anything like this? Will the epoxy last/hold up, ok? He said he used standard, hardware store grade, Devcon epoxy. Seems like it may be a nice intake to put on a set of 2.25” intake GM alum heads.
Race Director
Joined: Jan 2000
Posts: 13,017
Likes: 2,261
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
Re: Epoxy modified GM BB intake ? (66427-450)
Using epoxy on intakes and heads is very common in the race car world. As long as it is put in right, it will hold. You need to make sure the stuff used is able to withstand fuel. The stuff they actually use at race shops is pretty expensive, so I'm not sure it's the same as hardware store stuff. Might be though, just need to do a little research.
The other issue is that the reshaping of ports is pretty picky stuff. making air turn is not easy to do. Usually when heads are modified, they usually raise the roof and then fill in the floor with epoxy to reduce volume back and get a better angle toward the valve. Very little flow happens at the bottom of the port in most cases. That short turn is tough.
It's worth a try, but considering that intake is about right for a 396/427 and getting pretty small for a 454, I'd hate to reduce runner size too much when installing good flowing heads.
JIM
The other issue is that the reshaping of ports is pretty picky stuff. making air turn is not easy to do. Usually when heads are modified, they usually raise the roof and then fill in the floor with epoxy to reduce volume back and get a better angle toward the valve. Very little flow happens at the bottom of the port in most cases. That short turn is tough.
It's worth a try, but considering that intake is about right for a 396/427 and getting pretty small for a 454, I'd hate to reduce runner size too much when installing good flowing heads.
JIM
Racer
Joined: Jun 2000
Posts: 294
Likes: 0
From: WA
Re: Epoxy modified GM BB intake ? (66427-450)
Manley sells epoxy specifically for intake and exhaust ports. The intake epoxy comes in two sticks that are like putty. You mix them together and then lay it in the port and work it like clay to whatever shape you want. The exhaust epoxy seems like the same stuff as Sears filled epoxy. It comes in a tube of white and black making a grey mixture. It's a filled epoxy but tends to run and sag so you have to position the part to keep the epoxy where you want it until it dries - then shape it with a sanding roll.
According to David Vizards book on small block chevy cylinder heads, it works ok. I haven't run it in my engine yet.
According to David Vizards book on small block chevy cylinder heads, it works ok. I haven't run it in my engine yet.
Thread Starter
Safety Car
Joined: Mar 2002
Posts: 3,780
Likes: 442
From: Southwest MI
Re: Epoxy modified GM BB intake ? (427Hotrod)
thanks for the feedback......... like i said, i got it pretty cheap, figuring that i could always remove the epoxy and sell it.
I'll be using my notched '66 425 intake in any case .
:seeya
I'll be using my notched '66 425 intake in any case .
:seeya
