I was wondering, what is the hp limit of a a LTx intake. I know the LT4 would be more than the LT1.

For example lets use a common full bolt on LE2 355 LT1 that dyno's 400rwhp/380rwtq through a t56 and a 12-bolt. What gains, if any would be had by going to a victor junior with an elbow and a 90mm TB, fully dyno tuned either way? And would it even be worth it?

Just something I have been thinking about. Daring to be different, thats all.

 

I believe the fastest NA car with a stock ported LT1 intake manifold went 10.5, that's more than 400 rwhp for sure. There will be a gain from a single plane intake, and it should be proportional to the power output.

 

Hmm ...

Im in the same boat as you right now. I will be going to some type of heads/mild cam set up for now, with long range plans of a boosted 378/383. I wanted to do the intake now with the heads LE2/LE3 maybe? But am afraid to throw my money away if I can reach the power levels I wanted on a stock intake ported by LE.

 

Well, Im just wondering for curiosity's sake.

 

If it's any help, I plan to use the stock LT1 intake on a forced induction alcohol burner in the 750+ range. I mean, the intake wont be stock... it'll be ported... but I won't be going to a sheet metal or single plane.

 

I would imagine that a FI motor would not be hurt as much by the LTx intake b/c it's FI, now imagine your motor with a single plane.

 

I know of one race car that put 490rwhp to the ground, ported LT1 heads, street ported LT1 intake and a solid roller, goes low 10s over 3300lbs. Believe Ed Wright's car goes low 10s too LT4 383 NA and again over 3300lbs and I am sure he has the LT4 intake with porting as well.

 

so it seems that it would be more of a "dare to be different" kinda thing unless your making some real power, or its not's really worth it.

 

Seems like if your going N/A, its not worth it inless you are going HUGE hydraulic, decent heads. Most all of the solid roller cams are aggressive enough that on correct heads, they would justify having it.

To sum it up, once you are trying to break 500RWHP NA

Forced Induction is a little more forgiving.

But think of how few are running a single plane on a FI motor. It could have the potential to be a really, I mean REALLY mean ****ing motor.

 

Subscribing.

I have a Victor EFI in my shop right now. I already drilled it for the LTx heads, made a distributor plug, and started on an elbow going to a stock-style intake. My setup is a little different, though, since I'm turbo'd.

BTW, I've seen 48x rwhp with a stock LT4 intake, very big solid roller, 396 cid, etc. . .

Mike

 

I saw a small solid roller 383 with home ported aluminum lt1 heads 2.00/1.56 valves, and a port matched lt1 intake make 450 at 6100 rpm. Plus, it was a nitrous cam.

 

I was running a highly modded 396 with the lt4 intake with afr 220s had ignition brake up high rpms due to the opti blues am now running a single plane with big stuff 3 dfi and ls1 coils willl update when i get some numbers

 

why is it everyone has posted about these 450 NA plus rwhp cars but no one has one?

 

Ok, here ya go....or close to it..

A few on here have mentioned that stock intakes LT1/LT4 flow in the range of 240-250cfm. After, with welding the ports above the injectors, porting the intake runners until they bleed. Cutting the top off to get inside helps along with removing the cross over tube bump. They should then flow 275-285 per runner. I'v done all that plus raise the roof 2 inches. No way to have a before and after dyno (due to having to cut the end rail area and cutting the port to head side to get the right height) and or I might have tried that just to see...

 

It really wouldn't be that expensive to do it. The Vic Jr is about $320. Not sure if you could use the stock Lt1 fuel rail or not, if it did work it would look funny, but hey it would be functional.
Then a simple wilson elbow ($220) and any decent 90mm TB, or you could get a 4v TB and forget about the elbow. If it were me, I would try and convert my stock lt1 TB to fit by making my own elbow.