Hey Everyone, I was wondering if Chevy made BBC intakes that where oval port but in cross ram, 3 deuces, six singles, something along those lines, or is that strictly a rec port thing. Looking for something different to run on my 454 besides 2 fours or tunnel ram. Thanks
The only GM made intake that fits your list is a Corvette tripower...from 1967 to 69. 427 400 horse variation...kinda pricey these days. The crossrams and 6x2 variation of the crossram are square port head. I even had a Man A Fre 4x2 I intake setup for bbc once..but it was square port too. The only oval port multi carb intakes made aftermarket im aware of are tunnel rams and a low rise dual quads...
That’s what I thought. I have a set of Merlin O ports that I’m using and just want a different set up but I don’t want to run recs I’ll keep my eyes open for one of those vette set ups Sent from my iPhone using The H.A.M.B. mobile app
Your right but I already have the O ports to use and there good heads Sent from my iPhone using The H.A.M.B. mobile app
Not an endorsement, but the mis match has been done, a lot. Jim speaks the truth, re: square ports. But you already have a great set of heads. All the best in your search!
I thought about that just can’t bring myself to do it and I see you feel the same Sent from my iPhone using The H.A.M.B. mobile app
that's strange, since you want to put a crappy (but cool looking) intake on your good heads, why worry about the port mismatch? the intake sucks, the port mismatch isn't really going to make much of a difference. just playing devil's advocate here
I have used several different square port manifolds on oval port heads. Just for the street so not sure on full on performance. Just use the square port gaskets. Worked for me no problems. Jim
I'd rather go with a set of open chamber square port heads and and a high rise intake with the same ports..... But that's just me.....
I'd say that this is where Jim is thinking in tenths of a second gained or lost and others may be thinking visual appearance. If you are into "looks right" rather than "quicker" missmatched doesn't much matter. Agreed that Corvette tri power setup is beyond spendy.
Ok I need a bit of schooling here what makes a tri power set up or six single set up crappy if you can get the right cfm? I know that the tunnel rams work at higher rpms and I’m thinking the cross ram would be same. I’m building a street motor so I’m thinking single carb is going to be the way to go. I just thought I might be able to get the performance and look I wanted too but it seems like you get one or the other Sent from my iPhone using The H.A.M.B. mobile app
I just want to thank everyone who has responded to this thread. It’s nice to be able to bounce questions of people and get feed back Sent from my iPhone using The H.A.M.B. mobile app
stick a blower on it, and get it all! again, rectangular port heads are the way to go. The point I was trying to make is that you are wanting to use relatively modern technology heads, with an ancient technology intake and carbs. There is a limiting factor in there somewhere. Think about it.
This is very true and I see what you are saying. This is why I love this forum its nice to get different views on things. Thanks for your input Squirrel it has helped me out. Sent from my iPhone using The H.A.M.B. mobile app
I had a mid 6 second 1/8 mile, 3400 lb Camaro(untubbed, just slicks)I ran on the street and bracket raced for over 10 years with oval port heads and ran numerous square port intakes on it with no problems. It actually ran slower when I did use an oval port Edelbrock intake once, so never ran one again. The port mismatch actually created more airspeed and smoother low speed cruising throttle response.
Really I always thought mix matching the ports was a no no and would make less power this is very interesting to me Sent from my iPhone using The H.A.M.B. mobile app
That’s a good lookin engine but a little out of my price range would love a blower but the pocketbook won’t allow it Sent from my iPhone using The H.A.M.B. mobile app
It's not as important as people would have you believe it is. You can't hardly get any worse of a mismatch as the oval port to square port scenario, but it works great. I was also skeptical myself at first until I saw a local racer at the track one day have to pull a head because of a head gasket swap and a saw he was running his engine that way. I quizzed him about it and said he had been doing it for years and works great. That coupled with not many good intakes made for the oval port heads either, I did it as well. That was back in the late 1980's, so its a trick that's been done forever by big block guys.
I have read several tech articles over the years about port mis-matching not being a significant issue, but in a previous conversation with Jim, I decided to run my square port single quad manifold with the matching square port heads. My decision was based more on the fact that I have both the square port and good oval port heads ready to go, and not on performance gain or loss. If you do decide to mis-match the ports, think of what a conversation starter that would be. Mind you, they will only know if you tell them. Bob
Ok so I’m very curious about this whole mix match thing. I think I might just have to give it a test run and see for myself how this works. My O ports are after market and are big O ports so I can kinda see it working. This is definitely something to test on the dyno Sent from my iPhone using The H.A.M.B. mobile app
To run those numbers I ran in my car was close to 600 HP, so it couldn't have been hurting the performance too much. Plus back in the late 80's when I was racing the car, I couldn't afford square port heads, just wasn't in my budget back then. Many guys were running the 5.70 heads up class in dragsters and roadsters and often ran square port tunnel rams on oval port heads. It was done successfully long before I ever did, just followed their advice and it worked great for me also.
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