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RPM Air Gap/Victor Jr. Manifolds


Guest thinkmonkey

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Guest thinkmonkey

How have people's experiences been with these two intake manifolds? Do you guys prefer the low down torque of the air gap or the high speed breathing of the Victor? Any hood clearance issues found with any of these (JTR conversion)? Thanks.

 

-David

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I have the air gap and love it. Good torque down low, pulls to over 6000 easily, no hood problems with JTR mounts and 1 1/2" drop base air cleaner. It is cold natured in cold weathter. I open track my car, so the mid range is important to me. I haven't tried the Vic jr, but my experience with other single planes is that they really hurt the low end till you hit about 4K. Single plane would likely be the ticket for a high stall drag car.

 

John

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Depends on the motor to a significant degree. If your peak power is at or below 6500, I would run the air gap unless you plan fuel injection. In which case the Victor Jr. makes a better conversion intake. Overall power in the 2500-6500 rpm is very similar. I love my Victor Jr., but will probably do regular Performer RPM for my next intake.

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According to the comparo tests I've read vs airgap rpm, the victor jr is surprisingly close at lower rpms, then cleans up at higher. Your cam choice will determine which will work better. RPM has the edge for low end torque. In my situation I'd gladly have a little less low end as traction is already nonexistent. Driving today with cool temps, even a slight tip in, primaries only, in 2nd brings severe wheel spin. The victor jr fits fine under the hood, but recommend the early Z28 drop base repro air cleaner base. I run mine with a 4" K&N. Note there are different victor jrs, the lowest profile is the one that fits.

John

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Like John said. I have the "shortest" 2975 Victor Jr., but it is in my Camaro not Z. I turned John onto the Z/28 air cleaner, and nothing else comes close for clearance.

 

John, the GM factory cowl induction air cleaner has an identical base and would be trick if somebody was going to fabricate a fresh air hood. Hmmm. If you run the 3" filter, you could even run a 1" spacer!

 

FWIW, Joe Sherman's EngineMasters winning 365 ci motor made 604 hp (528 lb ft.)with a 3" filter. That motor absolutely ROCKS and should be the model for any hiperf street small block. Pump gas , hydraulic roller (236 @ .050!), WOW!

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Guest thinkmonkey

I just realized that I can't use the Victor Jr, because I'm going to be using the Vortec iron heads with the different bolt pattern (I'm getting the 350 HO GMPP crate engine). So, I can go for the RPM, RPM air gap, regular Vortec Performer Intake Manifold (holley or edelbrock carbs), or the Super Victor manifold. What do you guys think? I'm leaning towards the Super victor for greater high end breathing (although it is peaky according to edelbrock) but with the Vortec Performer Intake Manifold it has provisions for a holley 4150 carb so in the future I can use a vortech UNIVERSAL CARBURETOR ENCLOSURE for supercharging (although I hear that it won't work with HEI).

 

-David

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Unless you are going to run a camshaft with more than 240 degrees of duration at .050, stay with one of the single plane intakes. The Vortec heads are limited to .460 lift without mods, which rules out rpms above 6500 or so anyhow. Get one of the dual planes. Their is nothing wrong with the GMPP intake either. Doesn't the 350 hp motor come with an intake?

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Guest thinkmonkey

The deluxe package comes with the intake, distributor, carb, flexplate, water pump, and a few other things. I'm going for a slightly larger mechanical secondary carb and someothers things, which is cheaper if you buy the basic long block and add the accesories (Check out dec 2002 of Chevy HP magazine).

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dhans

 

I am installing an HO 350 using the performer RPM airgap and performer 600 cfm carb w/electric choke. Sweet looking package but not ready to drop it in. Right now trying to figure out the conversion from EFI in my 78 Z to a carb setup and have everthing work as intended.

 

:D

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Guest thinkmonkey

I'm pretty much ditching the z's (i have a 240) original electrical system. What started as a $900 car to 'freshen up' for high school has turned into a strip and dip, street legal, stripped interior, roll caged, v8 monster of a project. Snowball effect in it's finest.

 

I like the 350 HO. It's just over $2k for a brand new setup, those awesome vortec heads (does need mods for greater lift though, uses press-in rocker studs and the required use of center-bolt valve covers), a brand new iron block, and a warranty. Some say I should go for the rebuild, but this sounds good to me.

 

-David

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AROSSA, you can go to www.enginemasters.com and see the average numbers for all competitors, but not the breakdown. This months PHR, with the red 70 GTO on the cover has complete breakdown, but heres a snapshot from memory.

 

365ci 4.030 bore, SCAT 3.625 crank 2.40 (standard large) main journals, 2.00 (small journal) 6" Manley rods flat tops, hand ported AFR 215's (195c raw, but not the 195 head)angle milled to 57cc Isky 108 LSA, 282/282 232/232 .569/.530~ lift. 1.6 rockers on the intake, 1.5 on the exhaust. flat tops 11.4 compression. Super Victor intake, 930 Demon, 1 3/4 out of the box Heddmans. Heads flowed 310cfm on the intake. Peak powere was 604 at 6500 and 528 lb ft at 4800 or so. Real trick stuff is super thin .043 rings, coated piston tops and skirts, coated bearings. Off the shelf oil pan.

 

This is exactly how I would build a street motor except I would go 4.040 with stock stroke crank to keep the price down. Figure you could duplicate this to the tune of 550hp and 475 lb ft for about $6000 with careful parts seletion and assembly.

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Do you guys prefer the low down torque of the air gap or the high speed breathing of the Victor?

No functional loss in torque with my Victor Jr IMO. I've used both an 8004 weiand previously and then a Victor Jr. carb setup on my 327 and now roller 350 and subsequently an EFI Vic. Jr. intake. With all 3 setups low rpm torque was never lacking, shreds tires (good ones ;) ) from a 750 rpm idle with just an OEM like torque convertor with ease. The 327 was mildly cammed and so is my 350. IMHO they hype the Victor Jr. as race only moreso such that racers would not be running out to buy a 'truck' compatible intake etc. But local engine building gurus have run them on truck motors/mildly cammed for torque with great success and I've loved it on my sb builds as well. We're not driving lead sleds and I think some get too hyped on following build paths of quite different rides. I need a lot of driver input at low rpm's with my built 700R4 and sbc to keep it straight and under proper traction...I'd like to experience a 500hp Z at some point but certainly not for my daily driver 365 days/year. My control efforts required with my own moderate mill are enough for my needs :D
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