Air Gap Rpm Vs Victor Jr.

Well if the engine this is going on is in your sig.............it is the cylinder heads that are the problem (assuming the right camshaft) not the intake manifold. The Performer RPM is good thru 6,500 rpm. Same with the Air Gap. A GT40P head is just not going to cut it on a 347 cid engine at that kind of rpm

Sure porting the head helps, it just does not help enough. I think that if you swapped on a set of AFR 205 heads you would be shocked by how much power you would gain.

So instead concentrate on making power to 6,000 rpm. For one it is much easier on the stock short block. You can make a lot of HP with a stock short block if you keep the rpm's down. And a 4 hole spacer will work much better than an open spacer on a dual plane intake manifold. You can offset cyl. head restrictions by adding more Nitrous, or using boost. Which carb are you using? What is the cfm?

Even with the better intake your still bottle necked at the heads netting you hardly any gain. Your peak HP/TQ will still be below 6k rpms and trying for anything beyond that just isn't realistic with GT-40p heads. Besides, porting isn't all about removing material, it's where you remove it and being careful to not take too much away. Your intake you have now is fine, find some used aluminum heads and get a custom cam to reach 6500 rmps. A TFS stage 1 cam range is 2000-5500.

honestly it wont make a huge difference i wouldnt think... the heads are the weak point so thats going pretty much limit the rest.

FWIW we have a vic jr on the turbo car and have spun it will into the 9K range

9k rpms

FoxMustangLvr said:

9k rpms

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347" also

srtthis said:

honestly it wont make a huge difference i wouldnt think... the heads are the weak point so thats going pretty much limit the rest.

FWIW we have a vic jr on the turbo car and have spun it will into the 9K range

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True, but that Victor Jr. is only rated to make power thru 7,500 (naturally aspirated) having a turbo force air thru it helps extend the operating rpm's for making power. I built a 13.5:1 347 back in the day that we spun to 8,200 rpm using a Victor Jr. But that was also augmented with a healthy shot of Nitrous. On the engine dyno when the engine was run without the Nitrous, the power started to fade once we went past 7,500 plus rpm.

You have to spend lots of money to rev an engine that high (7500-9k) or it'd explode. Your cam and heads are not a recipe for over 6k rpms. New fuel delivery,cam and heads are what you need for starters, not intake. Or you could just start building your LS now.

The engines cited turning 8-9K were not stock blocks. In our case we used a Ford Racing "R" block.

foureyefox347 said:

Ok so I've been trying to research this, I'm kinda going toward the air gap but idk yet. I have a performer rpm with a one in. spacer right now and it kinda feels like it dies off at 6000. Now this is my daily driver I drive to work in summer time everyday. I'm Going to run a 100 shot on it too but i cant find anything on if pll have been spraying on the air gap intake. They are both the same price so I just need opinions on which one to get

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like the others have suggested, you are asking too much from your heads.