Performance Lacking in a 383 Build.

[88Stanger]

Well damn, sorry for the issues you have had.
I have a 383 stroker i am going to run, with Edelbrook aluminum heads (same or close to the same as you), full roller Howards Cam, Lifters and Rockers but the cam is not an RV grind i called and got a cam grind built for the 383, Muncie 4-Speed and 3:42 posi rear.
I am interested to hear what the engine builder has to say. I built my engine, but had the machine work done a respectable outfit in town and then me and my anal build mind took a week of measuring, testing, and such to build it. I fortunately have alot of the tools to test the fitments, not saying i know what i am doing, only saying that if it is bad or not right, i can only blame myself.
I wish you all the luck possible and look forward to your excitement of how "Snapping" the torque monster has!!!

[Ptjsk]

Originally Posted by '68OrangeSunshine

Is this in a Blazer [K/5] type truck? Even though GMC called them K/1500, not ''K/750''.
Or are you using Jimmy as a nickname for a GMC pickup?
4.56:1 is unusually low for a rearend on a light 1st gen suv. Most are 3.73:1 or even 3.07:1 in a half ton.
If you're talking about a 3/4 ton GMC, never mind. But 4.56:1 on a half ton Blazer is real low. And you'd do better with higher gears, like 3.73.

No, it's actually a Jimmy. It's GMC's version of the Chevy Blazer.

I placed the 410 gears in it when I restored the vehicle last year.

I'm running 33's on them, and I did install a gear vendor overdrive unit.

Pat

[Ptjsk]

Originally Posted by 88Stanger

Well damn, sorry for the issues you have had.
I have a 383 stroker i am going to run, with Edelbrook aluminum heads (same or close to the same as you), full roller Howards Cam, Lifters and Rockers but the cam is not an RV grind i called and got a cam grind built for the 383, Muncie 4-Speed and 3:42 posi rear.
I am interested to hear what the engine builder has to say. I built my engine, but had the machine work done a respectable outfit in town and then me and my anal build mind took a week of measuring, testing, and such to build it. I fortunately have alot of the tools to test the fitments, not saying i know what i am doing, only saying that if it is bad or not right, i can only blame myself.
I wish you all the luck possible and look forward to your excitement of how "Snapping" the torque monster has!!!

I'm hoping for information tomorrow! I'm curious to see if additional machining is going to be necessary.

Pat

['68OrangeSunshine]

Originally Posted by Ptjsk

No, it's actually a Jimmy. It's GMC's version of the Chevy Blazer.

I placed the 410 gears in it when I restored the vehicle last year.

I'm running 33's on them, and I did install a gear vendor overdrive unit.

Pat

OK, I get it. I thought the gearing sounded low, but with a GV/OD it makes more sense. With 4.10s your focus is off road, and a personal choice.
With three broken piston rods we know why you had no power. You were actually running a pumped-up 5 cylinder.
Better luck on your rebuild.
My '71 Jimmy is a 350/SM465/NP205/12Bolt-3.73Posi/ 33x12.50x15.
Yours is pretty.

[72c20customcamper]

Seems that more than one company is or had problems with their pistons TRW paid for the rebuild for my 66. Mine was catastrophic though 3 others had cracks around the wrist pins.

Absolutely no noise prior to damage

[jjzepplin]

Well that stinks man! I always use good Forged pistons in my rebuilds.

[Ptjsk]

Well...motor needs to be bored .040 to clean up the cylinder walls.

Ordered forged SRP pistons and all new bearings. Hopefully it will run like it was supposed to when it's back together.

[jjzepplin]

Sounds like a good start.

[Steeveedee]

.040 over what was already bored? Do you trust your machine shop? Was it a stock bore when it was stroked? I'd hate to see you throw more money down the toilet.

[Ol Blue K20]

Originally Posted by Steeveedee

.040 over what was already bored? Do you trust your machine shop? Was it a stock bore when it was stroked? I'd hate to see you throw more money down the toilet.

I'm sure that .040 includes the previous bore.

[Stocker]

Originally Posted by Ol Blue K20

I'm sure that .040 includes the previous bore.

That's what I took it to mean also.

[Ptjsk]

Originally Posted by Steeveedee

.040 over what was already bored? Do you trust your machine shop? Was it a stock bore when it was stroked? I'd hate to see you throw more money down the toilet.

Yea, I should have stated that it's going to go to .040 over from stock, as it was already .030 over and he just wasn't able to save it.

This mechanic is actually very dependable, highly desirable, and very hard to get an engine in line.

Fortunately, I had an inside line.

Pat

[Ptjsk]

Originally Posted by '68OrangeSunshine

OK, I get it. I thought the gearing sounded low, but with a GV/OD it makes more sense. With 4.10s your focus is off road, and a personal choice.
With three broken piston rods we know why you had no power. You were actually running a pumped-up 5 cylinder.
Better luck on your rebuild.
My '71 Jimmy is a 350/SM465/NP205/12Bolt-3.73Posi/ 33x12.50x15.
Yours is pretty.

Thanks for the comments.

Probably highly unlikely it will see much off road use, I just want to be able to pull a car trailer, or a camp trailer periodically.

Thanks for the better luck wishes. I'm hoping for far better luck too!

Pat

[Ptjsk]

Originally Posted by 72c20customcamper

Seems that more than one company is or had problems with their pistons TRW paid for the rebuild for my 66. Mine was catastrophic though 3 others had cracks around the wrist pins.

Absolutely no noise prior to damage

Wow, that's crazy! Sorry you had to go through similar issues too!

Pat

[Ptjsk]

Originally Posted by Ol Blue K20

I'm sure that .040 includes the previous bore.

Originally Posted by Stocker

That's what I took it to mean also.

Thanks Guys!