Hello Guys,

I am having my original 402 engine rebuilt using all of the original parts (besides the inside "guts"). I was wondering, how much of a difference will there really be between the stock lose rise cast iron intake manifold and an edeldbrock 2-0 performer aluminum manifold? Would it make a difference if I put a spacer between the original 750 cfm quadrajet carb and the intake on the stock intake? Let me know. Thanks!

I'd like to know the answer also. I just bought a 72 402 to drop in my 67, but looks like it will need rebuilt first

We've just finished some extensive testing on the '72 stock cast-iron intake from the LS-5, which is/should be the same one used on the LS-3.

The Q-jet intake used on the LS-5 platform will support 500 HP "as-is" and with some mild porting would probably be able to handle in the area of 550.

This number is based on a recent LS-5 (496 stroker) that came off the dyno with 460+ HP @ 5700 and 540+ Torque @ 3600 RPM with a 9.5:1 C.R., the Q-jet, and the factory exhaust manifolds. From the outside this was a 100% correct-appearing factory unit for a '72 Chevelle resto!

This intake, with a G.M. part number of 6263753, works reasonably well for what it involves. I would NOT recommend it for "maximum" performance. By the way, the Q-jet carb makes an excellent "all-around" performer.

Thanks, Gary in N.Y.

P.S. If you will be "chasing" higher HP number from the "small" unit, I would recommend another intake for add'l help! I would assume the '70 402" would have a very similar intake, possibly the same piece, but with a different part number?

Just don't use the flat, darn near a pancake, Q-Jet intake!!

My '75 454 P/U core engine had one on it when I got it. The carb flange was almost at the same height as the top front runner so it is LOW!!

OR..............

Gary, am I all wet and this is the one you are talking about????????

pdq67

Just don't use the flat, darn near a pancake, Q-Jet intake!!

My '75 454 P/U core engine had one on it when I got it. The carb flange was almost at the same height as the top front runner so it is LOW!!

OR..............

Gary, am I all wet and this is the one you are talking about????????

pdq67

Hi Paul, correct, it's the "pancake" style. It will support the HP numbers above. Below, the "high-rise" on the right should/would be capable of supporting 600+ HP relatively easy. Haven't tested any of these to date for "max" HP however, only on "stockers"!

The early BB's had a much better intake setup with the cast-iron Q-jet "high-rise" or better yet, the cast-iron "Holley".

Thanks, Gary in N.Y.

P.S. I'll put a shot here of the pair side-by-side. The one on the left was just removed from the "steel shot" blaster (appears to be aluminum) and is found on the LS-5 (low-rise) while the one on the right is from a recently delivered 100% correct '67 Camaro resto! Both these pictured are Q-jet's!
http://thumb8.webshots.net/t/60/460/9/18/9/2803918090044112208pDFhgj_th.jpg (http://good-times.webshots.com/photo/2803918090044112208pDFhgj)

Gary,

My old P/U's Q-Jet intajke is on the left!!

Just about like a pancake to me.

So it's really not all that bad if it's bull-nosed up top and opened up a schosh in the runners??

And guy's, to me this is good to know!!

Thx Gary!!

pdq67

My 454 ran a 12.15 @110 with a '69 Vette low rise that is only about 1/4" taller than the low rise iron model.

The low rise peanut port ones look the same from the top but are the worst intakes ever.
So don't confuse the two.

My 454 ran a 12.15 @110 with a '69 Vette low rise that is only about 1/4" taller than the low rise iron model.

is that the low rise aluminum intake that cam on 390HP/427 'vettes ?

Sounds like what he's saying. The 68 and 69 Vette 427/390s had a low-rise Q-jet intake in Aluminum. I saw a nice one on eBay for $250 yesterday. My Vette should have one of these. BUT, if I mounted one, then I'd want a stock BB hood. Would then need matching paint...snowball effect.
I'd heard the lowrise intakes, Vette 68 and 69 and all 70s onward cars were CRAPOLA. 12.15@110 is pretty respectable!

I've used the high rise iron manifold, both Holley and Q-jet on a bunch of engines. ALways ran good.

Yes, it's the factory aluminum intake used on the 1968/69 427/390 Corvettes.

I'd need a 3937793 for my late-build 68 Vette.
When I see them, they either have faults or I'm short of pocket cash.....
But I'm happy as hell with that tall PERF RPM and Holley!

I guess if they fit, height-wise, I would use a Weiand 8005 for a Q-Jet and a Stealth for a Holley carb.

Old intakes and certainly NOT stock jobbers, but I figure the power increase from either one would be worth it.

As always, jmho..

pdq67

guys in the FAST and pure stock classes that run LS6 cars do well with the stock low rise