383 build for heavy truck and towing

[travis]

I posted here a couple weeks ago about block prep for a low budget 350. That deal kind of fell apart for multiple reasons (owners budget mostly), so I did the right thing and ended up buying the 1985 3/4 ton 2wd suburban off the guy for an awesome price. Like I needed something else to work on

I’ve got 2 engines to work with here...a .030” over 4 bolt 350, and a complete worn out L31 out of my 1999 C2500 suburban. Both need completely gone through, the Vortec motor more so. I’ve got several sets of Vortec heads, a performer Vortec intake (2116 iirc), a 9895 Holley 650 spread bore carb plus multiple other square bore carbs, a couple of hft cams that would work well (comp 260ah-8 and a crane 272 energizer, but I’m not opposed to buying something else if needed), plus most everything else I would need. All I really need at this point is a crank and pistons to build a 383.

The truck comes with a supposedly 25k mile rebuilt TH400, but I also have an excellent 4l80e out of my ‘99. It has 3.73’s and weighs probably 5500-ish pounds. It will be towing up to 6000 pounds on occasion.

My ‘99 suburban was a dog even when running great...I want something better. How would you build it?

[ProPower engines]

Cost for a complete build is about the same regardless of which block is used.
And the vortec block offers a roller cam setup that is costly in the early block so thats a bonus there.
The sealing of the later block is better. You will have to decide on what heads to use if the vortec's are cracked.
There's more but you get the idea here.

[BillK]

My ‘99 suburban was a dog even when running great...I want something better. How would you build it?

What rear was in your Suburban ?? My 99 Tahoe (2dr 4wd) has more power than I could ever want in that vehicle. I towed a 5000 lb boat from Cape Cod back to Maryland a few years ago to do the engine for my cousin and it did just fine cruising down 95 at 75 mph That and it gets 21 mpg on the highway, even with 260K miles on it.

If I was going to do what you are doing I would use the drivetrain out of the Suburban, including the fuel injection. Seems almost backwards to stick a carburetor on it. I would bet that the factory injection would support the 383 just fine.

[77cruiser]

This is a nice one. viewtopic.php?f=1&t=43195

[travis]

My ‘99 suburban was a dog even when running great...I want something better. How would you build it?

What rear was in your Suburban ?? My 99 Tahoe (2dr 4wd) has more power than I could ever want in that vehicle. I towed a 5000 lb boat from Cape Cod back to Maryland a few years ago to do the engine for my cousin and it did just fine cruising down 95 at 75 mph That and it gets 21 mpg on the highway, even with 260K miles on it.

If I was going to do what you are doing I would use the drivetrain out of the Suburban, including the fuel injection. Seems almost backwards to stick a carburetor on it. I would bet that the factory injection would support the 383 just fine.

My ‘99 has 3.73’s as well, with 32” tall tires... and weighs about 6000 pounds with just me in it. It could have really used some 4.56’s with the 4l80e

[travis]

This is a nice one. viewtopic.php?f=1&t=43195

Very cool, but beyond my ability

[77cruiser]

This is a nice one. viewtopic.php?f=1&t=43195

Very cool, but beyond my ability

You could cut some corners.

[rebelyell]

Build the L31. North American-made replacement lifters very reasonable. Don't skimp on pistons; OE L31 are well made & have very good metric ringpack NPR offers an unusual replacement option for L31; they offer +10 over piston as well as +20, +30, +40.

[cardo0]

For cheaper cast cranks Eagle has a 3.800" stroke for under $400. But the cheapest cast 3.75" stoker crank is Ohio Crankshaft for less than $250. I'm talk'n only 1 piece rear seal cranks here.

You mentioned all you need is a crank.

I would buy the Ohio Crankshaft piece and use the savings for a correct cam. Keeping full duration under 270* a flat tappet will make same power as a roller. Using a short cam allows using a lot of OEM parts for valve train if not even the short block. No need for roller rockers or even forged pistons.

Have fun with it.

[pdq67]

How you coming along, Travis??

pdq67

[travis]

How you coming along, Travis??

pdq67

Sweating my arse off

[PRH]

Dished pistons, untouched 624 heads, a Thumpr cam, a Torker II, and an 850DP with some log manifolds and single exhaust(crimp bent of course).

It won’t have any power....... but it sure will go thru some gas!!

[travis]

Dished pistons, untouched 624 heads, a Thumpr cam, a Torker II, and an 850DP with some log manifolds and single exhaust(crimp bent of course).

It won’t have any power....... but it sure will go thru some gas!!

I’ve worked on stuff about that bad

I’ve never been a mopar guy, but a cousin of mine was, and he used to come up with some interesting stuff. He came up with a really clean ‘76 or so dodge 1/2 ton, with a ton of miles and a worn out 318. He added a Torker 340 intake and a 650 double pumper Holley and a way overkill complete MSD setup...while retaining the stock exhaust manifolds and single 2” exhaust, with about 90-100 psi cranking compression. It wouldn’t spin a tire in wet grass

[CGT]

Vortec without a doubt, more power, great detonation resistance, cheap way to run a hydraulic roller, no oil leaks with the late model sbc(or less of them)

I built a 383 using a late model block, using a cast 3.75 eagle crank...paid less than 200.00 for it then, 400 rods, and L31 replacement pistons in .030 with the 1.5 1.5 3mm ring pack. It can be done pretty cheap, but may not be for everyone. That piston will hit the counterweights at bdc due to the rod length, and that required some precision time with a DA grinder to crank to do some "reshaping"

Mine really wasn't a towing engine, but there is a thread on it here on speedtalk somewhere, it would have been around 2010-2011

[Walter R. Malik]

For heavy truck with towing applications, I would concentrate on making the most torque at 1,200 to 3,000 RPM and take whatever you get for horsepower.
Part throttle performance and response is much more important than Wide Open Throttle. Any camshaft much over 200 degrees @.050" is to big.