labreejr

Ive noticed most guys that go with a carb setup on their LS will use the Victor Jr intake opposed to the Performer intake. Why is this?

I have the performer intake along with a Comp 54-444-11 cam and 750 cfm Holley racing carb......good set up or should I change something?

speedtigger

iTrader: (16)

What is your transmission and gearing setup? And, what size engine and heads?

Doug G

Along with.... "how will it be used" ?
Street...performers fine.
Street/strip...performer "may" hold you back some at the track.
High winding stripper with a big stall, and gears...Vic Jr. is the usual "go-to" intake.

Pop N Wood

iTrader: (1)

That's a fairly good sized cam. Says it is intended for upper RPM power. The single plane might be a better match to that cam.

speedtigger

iTrader: (16)

It is not the size of that cam that is a problem in my opinion. From a duration standpoint, it is not really that large for a hotrod relatively speaking (224/230).

However, there is more to consider for his combo. If you look at the rest of the specs for that cam, it is 224/230 on 114 and has an intake centerline of 112. This means that he will have an intake valve close at 43 degrees at .050" combined with a cam that still has -1 degree overlap at .050".

To me, this means this cam was designed with the factory style long runner plastic intakes in mind. A single plain intake will want a sooner IVC and some overlap to bolster midrange power. I personally think this cam will be quicker with a dual plane intake unless he has a stall converter 3500 or bigger.

So, I say the real determining factor here is his transmission and gearing set up. Either way, I would probably advance that camshaft 2 degrees if it were mine.

Pop N Wood

iTrader: (1)

Yes, the spec numbers are less than an ASA cam. But the comp cam descriptions says the lobes make it an "all out race cam" intended for 2000-7000 RPM. So maybe aggressive and not good sized. Couple that with the "Holley racing carb" and my guess this combo is intended to rev.

The weight of the vehicle and even tires will come into play here.

I'm still betting on the single plane.

speedtigger

iTrader: (16)

LOL. That will probably be the funniest thing I hear all day. Gotta love catalog hype.

ZONES89RS

iTrader: (25)

Yea, I go by duration and LSA for the most part. Then factor in the other specs, and intended use.

labreejr

200r4 with 2800 stall. 3:73 in the rear. 6.0 lq9 with 317 heads milled .030 with comp ultra gold 1.7 rockers and neehive spring kit. Any suggestions on combo changes are appreciated in advance seeing as ive only installed the cam and double timing chain thus far

labreejr

Its going in my 84 t-top cutlass. right now it has 15 rallies on it. Its mainly a street/show car but I will take it to the track just to see what it does.

speedtigger

iTrader: (16)

With that combo, I would advance the cam 2 degrees and run the Performer RPM. I had a similar combo when I first put my car together and it ran hard.

1981TA

iTrader: (7)

I've got the Edelbrock performer sitting atop a bone stock 2001 LS1 long block, using an Edelbrock Thunder AVS 850 carb, and it runs very well. Chased down several "better" cars at this HPDE

labreejr

That's the one thing I was really considering changing......swap the 750 carb for an 850. Got a couple friends who did the same thing and their cars responded better to the 850.

labreejr

Advancing the cam does what exactly? Gives me more top end hp/tq? Will that hp be sacrificed in the higher rpm range?

speedtigger

iTrader: (16)

If you were to make a generalization, typically advancing a cam will move the RPM range to a lower RPM range. But, that is not the sole reason for doing it. What a lot of the cam gurus will tell you is that the timing of the intake valve close is about the most critical valve event in camshaft design. What many of them don't often tell you is that the ideal intake valve close event is directly related to the intake manifold and cylinder head intake port design. Most off the shelf camshafts for LS engines are designed for engines equipped with factory style long runner plastic intakes. Engines with those intakes can tolerate a later intake valve close event than carb intakes because the runners are so long and have a certain amount of port volume.

In my opinion, with your set up you could advance that cam between 2 and 4 degrees and pick up bottom end and midrange power without sacrificing anything notable for peak power. If it were mine, that is what I would do.

In regards to your other post about your carbureter, I think you will be thrilled with that Holley 750 mechanical secondary. If it were mine, I would not go to a 850 Holley carburetor. Even if you did gain a few horsepower near peak, it would not be worth whatever you might loose in the lower RPM range. I have tested this on my own car. Also do not compare a Holley carburetor to the AVS carburetor that the other Tech member was speaking of. Two completely different animals.

labreejr

Very informative as I am new to engine building as well as new to LS technology. Trying to retain and use as much info as I can towrds this build for it wont be my last.

Pop N Wood

iTrader: (1)

I was thinking more intended use. But now that we are no longer guessing, with that car and tires and the rev range of all the other components I still think a single plane would be a better match. I would look into a super vic if you have hood clearance. Yes, you will trade some mid range torque for more upper end HP but you have already done that with that cam. If you want to regain midrange, then something other than an EFI cam would be a better place to start.

That combo will run well as it is now, just a matter of what you are trying to do. I don't know if you just got deals but you put a good bit of money into that valve train and bottom end, you are rightly worried about carb size to feed it enough air, why limit the top end with the intake manifold?

Keep in mind Speedtigger started with a dual plane but switched to a single when it made his car faster.