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add more volume to a dual plane intake?

4688 Views 10 Replies 3 Participants Last post by  powrshftr
Hey guys, got another ? for the experts about my 327 combo. I have a weiand stealth dual plane that i was goin to use just because its laying around. The problem is i prob need a single plane. However the heads i got 220 cc rhs iron which are big for a 327. I really need some 200's but run what i got and thought the dual plane would compensate. My ? is, the int says power to 6800 rpm. Will it exceed this without adding more volume to the plenum? I was thinking a spacer. I dont know whether i need open or 4 hole and how tall. What would happen with a 4 inch alum open spacer from speedway? Would this work, or cause fuel and air charge turbulence? Any advice is appreciated.:confused:
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You'll probably have to get more specs on your 327 engine combo before I could comment on whether a spacer, or how much spacer would work. Compression ration, and cam specs will dictate what will work with the dual plane. Offhand I wouldn't go over 2" spacer with the dual plane, and I'd go open center. Rather than go taller I'd go to a open plenum intake. They're often found used on local ads like Craigslist for SBC very cheap. Then you can clean up your old intake and recoup some funds reselling it too.
thanks for replying. the combo is 10:1 comp, solid lift cam, either comp xs282s or xs290s, still deciding. RHS heads that are 220cc which i know are big thats why i running the weiand stealth intake to calm them down a bit. 1 3/4 headers, edelbrock avs 650 carb. Forged bottom end with speedpro pistons, scat procomp I beam rods and steel crank. This will be bolted to a mopar 4 speed trans with 2.66 low, 1.91 2nd, 1.39 3rd and 1:1 4th. 9 in rear with 5.43 gears. Just a cruise around old style hotrod setup in a tubbed 64 impala seeing 35-40 mph. Hitting the local 1/8 strip a couple times a summer. Thanks alot for your help
I have also been considering a tunnel ram setup for real old school look I'm after. Prob a couple of eddy 500's on a weiand tr. I'm a little nervous though with the 220cc heads in fear of them being too big and the eng trying to be lazy. However, with the 5.43 gear, 4 speed and big cam, it could just work. Thoughts or suggestions? Thanks guys
The cams you're looking at are pretty big, and I would not use the single plane regardless of risers. I'd get an open plenum, or go to the tunnel ram you're considering. I don't think with a 4 speed and the gearing you'll have trouble with a couple Eddy 500 cfm, and a Weiand tunnel ram.
I'm running the Isky 270 Mega Cam, which is much smaller at around .465" lift and 222 duration @.50" and the tunnel ram works great on my 327 with twin 450 Holleys. I'm running smaller heads with fairly stock 2.02" fueler heads. But my cam is a std. flat tappet hydraulic, and not a roller cam like the two you listed.
ok thanks 1946austin. The cams i listed are solid flat tappet cams, cannot afford the roller stuff. Even with the 220cc heads you think the TR will be ok? I was also looking at the old offy brand 360 TR which has the split plenum rather then the open. I was thinking it might work better? Also i love lunati due to their great customer service but, the comp xs290s solid has a better rpm range of 2800-7200 and has a 110 lsa vs the lunati 3200-6800 and a 106 lsa
When I put those numbers into Summit's site they both came up as Comp roller cams. I couldn't find those numbers under Lunati.
For the street a tunnel ram will almost always be a bit finicky, but the taller you go, the less issues they seem to have. I don't think an open plenum is a bad thing on a tunnel ram, as it gives the fuel a better chance to distribute to all cylinders, where individual plenums might create some rich-lean cylinders. That's a pretty common problem with tunnel rams that don't have enough volume, or where people try to go progressive linkage on dual carb tunnel rams. You need to have both carbs come in together, or whichever comes in 2nd will cause the cylinders closest to lean out.
they are solid lift flat tappet cams. here is the link to the comp xs290s and here is the link to the lunati
When I put those numbers into Summit's site they both came up as Comp roller cams. I couldn't find those numbers under Lunati.
Vall, thanks for the info on TR. I posted some links for the comp and lunati cams for you to look at.
I don't think trying to crutch the big heads with a smaller intake and carb is your answer....I would try to keep the induction side just as aggressive as the heads,so you can capitalize on all that airflow potential.
You're on the right track with running some deep gears in it,that will allow the engine to get the revs up easily and get the car rolling,then really rev once it gets moving.


Also,I would go 750 cfm on the carb of you haven't bought it yet.At 331ci (if your 327 is .030" over), with that much head and cam,and with those super deep gears,it will use every last cfm of a 750.
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