I think he got me....

[charx2]

I bought a 67 C10 on bags with what I was told a 383 stroker. It sounds very mean but I just have a feeling it's not a 383. My tires are very old and don't have much thread, the rear end is 3.08 w/o posi. I rode in my buddys 350 with 3.73 and it almost broke my neck when he stomped it. He also has put alot of money in the motor. I went home to see if i could get that neck breaking power. Well, I stomped it, and burned rubber for about 150ft until I ran out of road. Then I got on main strip and it just won't bite whatsoever. When I'm going about 30 I can stomp it but it just does'nt do what I would imagine a 383 would. Is their any way of telling if it's a 383 beside measuring the stroke? Possibly compression or something to that affect? I don't want to rip the motor out because if I do and it's not a 383, it will become a 383 and my wife will be very very very angry.... She's still mad at me for buying it but I just could not help it.

[dan42]

O.K...well, I don't think there's a way to tell without tearing down the motor, but if it's got 3.08's, than that will make a huge difference in the "perception" of power. There's a lot of other things that might not be quite right as well; i.e, carb adjustment, last tune, timing, plug wires, air cleaner, etc. It sounds like you have a little buyer's regret right now. Get it running perfect and then decide.

[dakman]

look at or feel the harmonic balancer and see if it's a balanced one, it should be if it's a stroked 383. Not too many people build them internally balanced due to big $$.

[michael bustamante]

Originally Posted by dakman

look at or feel the harmonic balancer and see if it's a balanced one, it should be if it's a stroked 383. Not too many people build them internally balanced due to big $$.

what do you mean feel it, are there counterweights on it orsomething?
dont mean to steal the thread. sorry

[Cole Trickle]

I wouldn't worry about comparing it to your buddies 350.

You could build a 350 with all the goodies (Aluminum heads,cam,etc...) that would smoke a cheap 383. On the flip side inches are inches and once good parts are added she will run strong.

Sounds like you need tires more than more hp...

[Hair]

Originally Posted by Cole Trickle

I wouldn't worry about comparing it to your buddies 350.

You could build a 350 with all the goodies (Aluminum heads,cam,etc...) that would smoke a cheap 383. On the flip side inches are inches and once good parts are added she will run strong.

Sounds like you need tires more than more hp...

Amen!
"383" don't mean squat. If you find that it is only a good bored over 350 you aint lost nothin. Anyway, you'll never know what you have as long as you're spinnin tires.

[charx2]

Ya, I did look at the harmonic and it doesn't quit look big enough. It's actually pretty small. I just replaced all spark plugs and wires, I do need a bigger air filter because the one I have is tiny. I'm just praying it is a 383 but was rebuilt "cheap".

Yeah, the tires are dry rotted and almost bald, I have 3.73 and a posi in my room just waiting to be installed after I get a new panhard bar to straighten out my rear end, it sits about 2-3 inches to the right at riding height! Going home now to check to see if the harmonic balancer is balanced...

[Hart_Rod]

The only reall way to find out is for the previous owner to produce the build sheet for the motor or to tear it down. Gears make a huge difference. You can take a weak motor and put it in front of some steep gears and you'd think you had it supercharged or something. Well maybe not quite that much, but it makes a big difference. That's usually why you will find 3.73s and 4 speeds in a lot of "farm trucks", even with a 6 cylinder. It doesn't matter how much power you have if you can't get it to the pavement.....

['72customdeluxe]

You could pop the heads off and check the stroke

[67/72junkie]

383 is a 350 block with 400 crank.If it has a stock gm balancer it should have a 400 balancer and all stock 400s have a section that is dipped in for a few inches on the outer diameter.All other stock small block balancers will be smooth all the way around except for the little grove to mark top dead center.Some after market 400 and 454 balancers have a weight that bolts on the inside lip of the balancer 350s and other small blocks will not have the weight.It should also have 400 flex plate and it will also have a weight several inches long spot welded to it and 350 doesn't.If you like the truck 350 or 383 isn't that much differance.Also 400 balancer is the large diameter one and about 2" thick if stock.any after market one should have part # that you can check with summit etc parts catalogue.Hope this helps.

[69halfton]

also... consider how old the rebuild is on the 383... if its getting to be like 6 or 7 years old, and the P.O has really rung it out for the past years, it could quite possibly be making less power then a fresh, expensive 350...might need to be rebuilt... again to be up in the power range you'd like it to be

that said, but 383 will roast 33in tires well over 100 feet, and both of them... but I have 3.73 gears and its less then two years old

[AH619]

i have a 388 in my 72 swb 4x4 with 373 gears. and an auto. i built my son a much less expensive 355 and put it in front of an auto with 410s. my sons truck will smoke mine out to about 80 mph. then hes through and mine is just starting. but i get 12 mpg and he gets about 5. also the power range of the cam and intake set up could be more for mid range instaed of low end????