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-   -   new 383 engine for 90 blazer? (https://blazerforum.com/forum/engine-transmission-35/new-383-engine-90-blazer-96538/)

okiehuntr 03-23-2018 05:07 PM

new 383 engine for 90 blazer?
 
threw rods on my 90 Blazer 350 TBI, have decided to replace it with a 383 stroker, would really appreciate any and all input...friend said I should get between 300 and 350 HP, another person told me 285 to 300 HP max...trying to stay with original cam and carb. I know the heads would make a great difference but I'm short on $$$ and need it done for 4 to 4500
thanks

oldeerslayer 03-25-2018 04:04 AM

Why a 383? If you haven't bought the engine yet be sure the engine is the same year as the 350 you are pulling. A lot of the eBay 383's are based on the older 2 piece seal left hand dipstick motors. Your pan and flexplate won't work. Among other things. Be sure the engine has been balanced. That's critical on a stroked motor.
I personally would never put in a new shortblock with an old camshaft. Maybe on a later roller cam motor, but not on flat tappet cam. In fact what I'd look for is a 383 roller cam shortblock. They did do some TBI 350's with them. Caprice and Roadmaster had them from 89-93.
As far as the 285-300hp vs 300-350 goes, does it really matter. On the low end you are talking 15 hp difference and your butt dyno won't know the difference.How much hp you have is just beer talk anyway. You haven't given the cam specs, compression ratio, or any other specs to base an estimate on.
Unless you plan to drop a grand on a good dyno tune, your ECM will also limit any gains with a 383.
Go with a good quality 350 and save your self time, money and headaches. Tell your drinking buddies it's a 383. There's no way to check once it's in.
I have a 377 in my 98 ZR2 and that figure just draws blank stares. If I ever build another it'll be a 350 and I'll spend the extra money on heads and a good tune instead of a stroker crank.

Rusty Nuts 03-25-2018 05:32 AM

Hey Bro, does that mean your 377 is actually a 350? Sounds like someone owes someone a beer.

oldeerslayer 03-25-2018 08:05 AM

Actually it's a 98 Vortec 350 that was still within .001 on the bore so I used std 4" Speed Pro hypereutectic 12cc dished pistons and perfect circle moly rings after flex honing the bores. Had it balanced to within 1 gram. Since the deck height stock is .025 I run a ,025 head gasket to achieve optimum quench of .050 and a 9.89 static compression ratio.
But at the bar I tell everyone my seat of the pants dyno feels 375 HP. A full 100 more that the original 350 had. Starts good discussions and is an exaggeration. Feels more like 300.
Not much gain for a lot of money IMHO. And that is with fresh Vortec heads and factory roller cam.
As stated I think the stock tune is my big limiting factor. Not any GOOD places in the frozen tundra to get a good tune. Been hearing some good feedback about a place a couple hundred miles away in Iowa I may try next time I feel like dropping $800-1000 on something so subjective.
Unless anyone knows of a highly respected place in Chicago.
Think I may build a better exhaust system first. That's all stock except the gutless cat.


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