Early 80s 355 or 383 T.B.I crate engine

[ColoradoChevyGuy87]

Preparing to replace the motor in my 94 GMC 1500 and I need some advice on which route go go.
Option #1- I have a pre 87 four bolt main block, already .030 over, internals have been balanced and appear to still be in great shape, has a set of Worlds 1-037 heads. Clean everything up and put back together with new rings and bearings, install new roller cam and lifters, rework heads with new valves, springs, and rockers and then modify a tbi intake to bolt to the older heads (I want to stick with a tbi manifold for accessory mounting locations)
Option#2- TBI 383 crate motor
I feel like option 2 is probably the least amount of work and the way to go, just want to make sure I'm not missing something and going to regret not putting the work into the older motor.

 

[Schurkey]

The older block will require a really-expensive cam and lifter set, and the goofy aftermarket cam bumper to set end-play. You'll also need the older flexplate to fit the older crankshaft. The block "can" be modified to fit a step-nose OEM roller cam and thrust plate...but it's not easy. And you'd still need really-expensive aftermarket lifters.

Define a "TBI 383 Crate Motor". GM doesn't make one. Aftermarket might. You'll be playing games with the computer tuning, and likely raising the fuel pressure. And you'd most-likely still be stuck with the crappy swirl-port heads. At least those heads will allow the TBI intake manifold and TBI manifold gaskets without mods.

When I looked at the TBI intake manifold, I couldn't see how it could be modified to work with older heads having all the intake bolt holes in the same plane. Someone else on this site said they did grind a TBI manifold enough to work with older heads--but I don't see how that's possible.

When it was me, I used a GM "ZZ" style intake manifold, with adapters to mount the ignition coil and EGR, and a flat-plate TBI adapter over the Q-Jet mounting flange. I also had to "adapt" the quick-coupler for the heater, and modify the vacuum pipe that connects to the brake booster and the mounting for the EST module/MAP sensor.

I got the strut rods for the alternator and belt tensioner to fit, but I'll have to fabricate a new strut rod for the A/C compressor to align with an intake manifold bolt rather than the OEM boss on the manifold that the ZZ manifold doesn't have.

Using the TBI manifold would be HEAPS easier...IF (big IF) the bolt holes can be reworked to fit the older heads.

 

[Hipster]

Not sure what those heads are but if non-vortec type chamber would probably pass. Last set of heads I had freshened were north of $700 at a machine shop, needed some guides but no seat replacements.. Better ways to do things now such as sourcing a roller ready vortec block.

 

[Erik the Awful]

I'm not a fan of two-piece rear main seals. Personally, I would try and find a later block. However, I don't think it would be rocket surgery to put one in.

A $5 cam button will eliminate the need for the cam retainer plate. You can probably tap the block and install some all-thread and run the later factory roller lifter setup, but I won't guarantee it. I haven't owned a two-piece rear main block since I rolled my '81 Camaro's 305 off into a dumpster back in 1999.

You might be able to get away with running the earlier manifold without the center bolts (Vortecs don't even have the center bolts), but I'd hog the center holes out and throw some bolts in them.

Flexplates? Educate yourself with this link:

Small Block and Big Block Chevy Engine Flexplate Guide

Over several generations of small block Chevy (and big block Chevy) engines there have been several changes that dictate what flexplate works with them. We’ll help you determine the correct flexplate for your Chevy engine in this buyer’s guide.

www.speedwaymotors.com

 

[Schurkey]

Lifter bores aren't tall enough on the older blocks, and don't have the flat tops for the dogbones to ride on.

 

[ColoradoChevyGuy87]

I'm not a fan of two-piece rear main seals. Personally, I would try and find a later block. However, I don't think it would be rocket surgery to put one in.

A $5 cam button will eliminate the need for the cam retainer plate. You can probably tap the block and install some all-thread and run the later factory roller lifter setup, but I won't guarantee it. I haven't owned a two-piece rear main block since I rolled my '81 Camaro's 305 off into a dumpster back in 1999.

Yo

Not sure what those heads are but if non-vortec type chamber would probably pass. Last set of heads I had freshened were north of $700 at a machine shop, needed some guides but no seat replacements.. Better ways to do things now such as sourcing a roller ready vortec block.

Not sure what those heads are but if non-vortec type chamber would probably pass. Last set of heads I had freshened were north of $700 at a machine shop, needed some guides but no seat replacements.. Better ways to do things now such as sourcing a roller ready vortec block.

u might be able to get away with running the earlier manifold without the center bolts (Vortecs don't even have the center bolts), but I'd hog the center holes out and throw some bolts in them.

Flexplates? Educate yourself with⁰ this li000nk:

https://www.speedwaymotors.com/the-toolbox/smal

9

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009000080000⁹⁰8⁹⁹9⁹⁸899899 ⁹0⁹The older block will require a really-expensive cam and lifter set, and the goofy aftermarket cam bumper to set end-play. You'll also need the older flexplate to fit the older crankshaft. The block "can⁰" be modified to fit a step-nose OEM roller cam and thrust plate...but0 it's not easy. And you'd still need really-expensi0ve aftermarket lifters.

Define a "TBI 383 Crate Motor". GM doesn't make one. Aftermarket might. You'll be playing games with the computer tuning, and likely raising the fuel pressure. And you'd most-likely still be stuck with the crappy swirl-port heads. At least those heads will allow the TBI intake manifold and TBI manifold gaskets without mods.

When I looked at the TBI intake manifold, I couldn't see how it could be modified to work with older heads having all the intake bolt holes in the same plane. Someone else on this site said they did grind a TBI manifold enough to work with older heads--but I don't see how that's possible.

When it was me, I used a GM "ZZ" style intake manifold, with adapters to mount the ignition coil and EGR, and a flat-plate TBI adapter over the Q-Jet mounting flange. I also had to "adapt" the quick-coupler for the heater, and modify the vacuum pipe that connects to the brake booster and the mounting for the EST module/MAP sensor.

I got the strut rods for the alternator and belt tensioner to fit, but I'll have to fabricate a new strut rod for the A/C compressor to align with an intake manifold bolt rather than the OEM boss on the manifold that the ZZ manifold doesn't have.

Using the TBI manifold would be HEAPS easier...IF (big IF) the bolt holes can be reworked to fit the

Not sure what those heads are but if non-vortec type chamber would probably pass. Last set of heads I had freshened were north of $700 at a machine shop, needed some guides but no seat replacements.. Better ways to do things now such as sourcing a roller ready vortec block.

World Sportsman heads. Around $1k aftermarket heads claimed to be up to a 70hp bolt on.

 

[PlayingWithTBI]

Option#2- TBI 383 crate motor
I feel like option 2 is probably the least amount of work and the way to go, just want to make sure I'm not missing something and going to regret not putting the work into the older motor.

If you want a 383 crate motor, you'll be stuck with a Vortec style short block. If you wanna stroke a TBI 350, that's a different story. They sell stroker kits for them including crank, pistons, rings, bearings, etc. I'm sure you know that. Then get a set of aluminum TBI heads to stick on top. What's your budget will probably be the deciding factor. If you don't have a competent machine shop nearby, go with GM Performance or Blue Print, don't trust those Auto Parts store junk built by ATK etc. You may have issues mounting TBI heads on top of a Vortec block but, you can easily overcome that.

Taking a phrase from @Schurkey - "when it was me" I went Blue Print

GM SB Compatible 383 c.i. Engine - 436 HP - Short Block Plus

Description: HP & Torque: 436 HP / 443 FT LBS Compression Ratio: 10.0:1 Hypereutectic Pistons Cast Steel Crank Block: 4 Bolt main 4.00" bore Passenger side dipstick Align honed main bearing bore Cylinders honed on computer controlled machine to within .0002 straightness and roundness Cylinders...

blueprintengines.com

Then, tune it!

 

[Erik the Awful]

Lifter bores aren't tall enough on the older blocks, and don't have the flat tops for the dogbones to ride on.

Good to know. I have heard that the max lift you can safely run with the stock roller lifters is around .530", or they can (ock in the bores. Supposedly replacing the dogbones with the later LS lifter guides is a fix. I haven't tried them yet, but I have a set for my $150 350. Try at your own risk!

Chevrolet Performance 88958652

Free Shipping - Chevrolet Performance 88958652 with qualifying orders of $109. Shop Lifter Link Bars and Guides at Summit Racing.

www.summitracing.com

Then get a set of aluminum TBI heads to stick on top.

He already has a set of World Products heads.

@Shaggy Can we please get c o c k unblocked? Or at least unblock c 0 c k? [I promise that I'm trying really hard to avoid the obvious joke]

 

[PlayingWithTBI]

He already has a set of World Products heads.

Yeah, FWIU cast iron with 200 cc runners. Besides not being drilled for TBI intake the runners won't help with low end torque. I'd save them for another build later.

 

[Hipster]

http://

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World Sportsman heads. Around $1k aftermarket heads claimed to be up to a 70hp bolt on.

Maybe be bolt on 70 hp as compared to a 80's smogger head of the era, maybe not so much as compared to a roller cammed vortec engine. 200cc a bit big for 350ci but would be right at home on a 383. pretty close to a vortec style chamber. What don't know is if the holes on the ends of the heads where the typical gmt 400 accessory brackets mount are in the same place. I think there were some differences there from one era to the next.