Looking for a Whipple for 5.7 Vortec

[L31MaxExpress]

And as soon as they cammed it. . .

Yes it does still make good low end torque, but not as good as it did with the smaller cam.

Did you notice the average torque from 2,500-4,800 rpm had a substantial increase. From 456.3 to 467.7. When I am under heavy throttle/load I am never under 3,000 rpm for long. Towing my 383 lives in the 3,000-5,200 rpm range.

 

[Supercharged111]

I did see that, but when I tow my RPMs are typically under 2,500 so the answer here really depends on where OP's motor is going to live. Before the blower I spent a lot more time at 3,000+. Even with a measley 4psi the truck typically holds 1 gear higher than before. I imagine near sea level the boost would be 7 psi.

 

[Christian Steffen]

I did see that, but when I tow my RPMs are typically under 2,500 so the answer here really depends on where OP's motor is going to live. Before the blower I spent a lot more time at 3,000+. Even with a measley 4psi the truck typically holds 1 gear higher than before. I imagine near sea level the boost would be 7 psi.

A little bit of boost goes a long way. I can't believe how different things feel at even a couple psi.

 

[Hutchinson]

Sorry guys, didn’t want my question creating controversy,.... my original goal was a low RPM torque grunter, that’s why the out-of-box HT383e’s 444 torque at 3000RPM appealed to me, because my truck’s 4x4.
I’ve built engines like L31max is describing (truly enjoy it too) in a 2WD S-10 with a hopped up 305HO (man, what a wild ride that was,....whiteknuckled quit a few dudes). And in a 67 Mustang fastback 390 original big block car (shouldn’t have sold that one). And in an 82 F-250 where I slide a 71 351 Cleveland 4barrel in it,... that was a slap ass smoker too. Several more not mentioned, over the years. All had intakes, cams, lifters, headers, etc changed.
My last build was a 57 cab, 58 front end clip, 56 bed 3100 Chevy Apache truck, sitting on a 74 3/4 Ton 4WD frame. Pulled an 88 454 4WD engine, trans, xfer case, springs and axles and slapped underneath,.....it was cherry. Couldn’t stop at a gas station, without talking to people for 10 minutes. I spent over a year building that truck, then, some sorry *ucker stole it from me. Never saw that truck again.
For this one, I was going for tough dependability, that will stomp a little *ss when I wanna play,.....hahaha. You know what I mean,.....

 

[Hutchinson]

Both you guys are experts at these trucks,....Supercharged111 is a wiz at boost, I’ve been reading his stuff for a couple years. And L31Max has a quick Express Van (I believe you posted some videos showing your instrument cluster at night hauling tater),... who does that kinda stuff with a van??? That’s cool dude. All 3 of us, as well as, a lot of other dudes on here, can answer just about any question people have about these trucks. We’ve played with them enough, for sure.

 

[Supercharged111]

I wouldn't go so far as to call it controversy, we're both right but we both have different preferences. A heads cam 383 would whoop my ass in a drag race and drive good empty, but it's not what I'd want to pull a trailer. Hell, a 383 isn't completely out of the question long term, but I don't expect my 350 to give up the ghost any day soon.

 

[L31MaxExpress]

Was not trying to create controversy myself just pointing out that a 383 can be made to run much better without the complication of adding a tiny blower that you will likely find lacking on the 383.

I tuned an 0411 pcm swapped whippled 305 Vortec here locally for a friend. It was pullied to the max and only made 10 psi on the 305. The 305 had the stock cam and heads. The same pulley set on a stock 350 makes about 6-7 psi. On a 383 it would be even less. Maybe 4-5 psi max. At stock pulley ratio you would probably be lucky to make 3 psi.

That was the point I was making. I also firmly believe you would be forever stuck burning the highest octane fuel available with the tiny little cam in the HT383.

As the dyno tests on the carb HT383 show, I think you could gain a considerable amount of power without going deeper into the engine than the rocker arms and intake manifold.

With the stock L31 truck intake manifold and the stock stamped 1.5:1 rockers you are probably lucky to make 310 hp. If you upgrade the rockers, intake manifold and improve the air intake path combined with headers and a adequately sized exhaust you could get closer to the 380 hp they made with the stock cam, 1.6 rockers, air gap intake and 750 carb. I don't think a stock HT383 with the truck intake manifold and a whipple could get to 380 hp.

 

[L31MaxExpress]

I wouldn't go so far as to call it controversy, we're both right but we both have different preferences. A heads cam 383 would whoop my ass in a drag race and drive good empty, but it's not what I'd want to pull a trailer. Hell, a 383 isn't completely out of the question long term, but I don't expect my 350 to give up the ghost any day soon.

My lack of space for a blower kind of dooms me to rpm for power. Also no desire to mess with a mid mount turbo. Hence why I have a 5.13 gear and rely on turning a little RPM even in OD. The 383 pulls really well at 2,850 rpm @ 70 mph. Only kicks down on steeper grades. When it kicks down its still only turning ~4K in 3rd gear.

 

[L31MaxExpress]

This is more where I was going as a starting point.

Out of the box HT383 with a 625 carb
Peak HP: 338.1 @ 4,400

Peak Torque: 444.3 @ 3,400

Average HP 2,500-4,800: 292.6

Average Torque 2,500-4,800: 424.0

Torque at 2,500: 431 lb-ft

HT383 with 1.6 rockers, performer rpm airgap intake, 750 carb.
Peak HP: 379.4 @ 4,600

Peak Torque: 474.3 @ 3,700

Average HP 2,500-4,800: 316.3

Average Torque 2,500-4,800: 456.3

Torque at 2,500: 449.9

The stock Vortec truck intake manifold flows worse than the 625 carb and the mid rise dual plane first tested on the HT383. With the L31 intake that power number would be more like 310 hp @ 4,200.

 

[run96k3500]

YOU HAVE ONE???? For sale??? Fabing a plenum, I can do. Is it complete/everything needed to plug and PLAAAAAAY?

Thanks guys,.... and yes Sir, i’m on HPTuners/ do my own 0411 tuning (not an expert, but, not too bad),.... guys on HPTuners forum have helped me a lot. A lot of good people there.
I hear you guys on intake, heads, cam, 1.6 rockers, etc. I’ve done all that research in the past too. That Edelbrock intake did peak my interest,.... I looked at the questions (on the Summit page), one question’s answer said no, won’t work on 96+, the other question answer said it would. Ok, so, now I need to call em. Has anyone put one of these on their 96-99L31’s? Is it direct bolt on/ any fab required? I believe OlBlue did his (on HPTuners), but could be wrong.

Yes i have one and it was just rebuilt at Jon Bond and hasn’t been installed since the rebuild. Also selling the 454 that it was originally installed on.


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