JW's 383 build

Messaged ChuckN about the die casts he had for sale and mentioned that I too am working on a 383 build. Although he suggested that I share my build on his thread I don't want to cobble it up with my slow pace. Alas mine is not for a Squarebody but instead for my '79 Cutlass. I have owned this car since August 2017 with the original 305, 2.29 rear, and first a TH200 that took a crap, now a used TH350 that has developed a massive fluid leak at the front end. Since there is a TKX 5-speed, clutch pedal kit, and 3.42 geared rear axle upgrades in my basement I'm planning to do those upgrades first this spring, then the 383 swap this fall. Enough about that- here's the 383 plan:
'89 350 block- roller cam ready, 1-pc rear main, fuel pump boss
Bored .060" over(technically 388"), Scat 3.75" crank, Summit cap screw connecting rods, Summit 17383C-60 pistons, Summit 8802 hydraulic roller cam (218/[email protected], .525/.520 lift, refurbed 062 Vortec heads, Performer intake, to-be modded (per Cliff Ruggles book) Q-jet, Hedman 68608 mid length headers.
Should be about 9.7:1 compression at .005" deck clearance and .041" head gasket, hoping to run 87 octane gas.
Initial boring, decking, head resurfacing done locally, taking to another shop for balancing.
Shooting for about 370hp, 400ft-lb?? Wanting a trouble free cruiser with a little oomph- so what do you guys think?

You may have heard "Where there's a will there's a way", well there is also "If there's an impatient dumb*ss- it's gonna happen". I don't currently have a hoist but wanted to get the block off my trailer and onto a stand without a hernia, so I rigged up this mess:

On the stand- cam bearings, freeze plugs, and oil galley plugs installed at machine shop. They also ran a machining program on their mill for strokercrank clearance. Cam card.

Have your machine shop 4 bolt it and ARP stud it, overkill perhaps but my OCD has never allowed me to do a 383 build with a 2 bolt block, 2 bolt main caps tend to "walk" with an aggressive build, I'm just not a fan, cheap insurance is real ! You also mentioned drivability, consider Edelbrock's new and affordable throttle body injection that will undoubtably be more reliable than Sniper... You'll love yourself for it so will your motor... Let'er RIP !!!

Fastduramax said:

Have your machine shop 4 bolt it and ARP stud it, overkill perhaps but my OCD has never allowed me to do a 383 build with a 2 bolt block, 2 bolt main caps tend to "walk" with an aggressive build, I'm just not a fan, cheap insurance is real ! You also mentioned drivability, consider Edelbrock's new and affordable throttle body injection that will undoubtably be more reliable than Sniper... You'll love yourself for it so will your motor... Let'er RIP !!!

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Machine shop rates have gotten ridiculous. I had my 496 block set up with Dart Big M splayed caps, bored and honed, and decked, grand total was $2K in labor.

Next time I do a splayed main block it will just come direct from Dart.

Understood- cleaning, crack checking, boring, decking block and heads, stroker clearancing, cam and core plug install hit me for $1025. Still have to get it balanced. Fortunately all the big parts are bought and paid for.

What year is the cast # on the block ? Is 1989 cast date correct in your post? '89 block .060 over yikes

Curious to see total dinero $ you put into the long block assembly

It's an '89 or '90 block- I would have to check to be certain- two local machine shops said .060" over would be fine. Time will tell. It had been "remanufactured" once before when I bought it at .040" over, hence the .060" over. As filthy as it was I hoped it was untouched but that was not the case.

Nice work man! Keep it up. I like that cam choice.

IMHO the two bolt wouldn’t bother me- it’s pretty common to run a two bolt main as long as you’re not going north of 500hp and spinning it past 6500. Just run some good hardware to keep it together.

You’re doing better than I am, timeline wise. The shop that I’m working with is super booked up and is a one man show with a part time helper. Your machine work is a little cheaper than mine, I’m guessing it’ll be north of 1100 when it’s all done.

Oh, do not despair, this process started last May (2025)- a good 10 months at the machine shop. I told them I was in no hurry. Waited for them to say .060" over was good, I ordered pistons, three months later still not available, ordered different pistons, blah, blah, blah. I picked up the rotating assembly Wednesday from the shop that did the balancing- another $325. With my relatively mild cam and head specs I don't expect more than 400hp and 62-6300 rpm at the (very optimistic) upper extreme. The Milodon 32250 3/4 length windage tray kit I picked up recently has studs for the three center mains which will help will help with clamping pressure and main cap stability. I probably won't assemble until the fall- gotta wring the last of the life out of the 305.