I have found for sale a 1975 442 455 with "unknown" auto tranny. It is in non-running condition, no carb or alternator. The stock tranny is still attached.

The engine spins by hand. It has J heads. I know they are the least desireable ones.

Can any shed some more light on the combo for me. Of course they worked fine when the car was parked ??? years ago.

What would these be worth as a core setup. Would you think that the tranny should be a 400th?

Last question, what would the performance be like with a fairly stock '75 455 with 10.25 pistions be like with the J heads and a 1970 BBO quadrajet (a 251).

This setup would replace my 350/350th setup in my 1968 Cutlass. I have a 4.10 rear diff.

I want to slowly collect peices to do this build, since I am happy with the 350, but since I am already a frankencutlass I might aswell keep going.

Thanks for any input.




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With a 4.10 gear, I'd just mod the 350. you're going to run out of steam pretty quick with that gear and a 455, although you'll get there pretty quickly

 

Thank you Mark. That is the answer I probably want. I am also constantly looking for a good local core 200R4 to build. I know a 1:1 350th or 400th is not the best with a 4:10 rear. I know none of the real specs for my 350sbo. It has a 650 holley and edelbrock preformer intake. I had new head gaskets and all seals done to it about 10 years ago by a professional rebuilder/machine shop. They reused all the mechanicals except for a few rockers. I was told it was about 9.5:1 with a slight cam. But that's all I know about the internals. It's a '76 block that had been rebuilt by the PO to drag with on the weekends. Maybe I should just big valve my #5 heads and maybe ask you for a cam in the future. It never hurts to keep looking.


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Sounds like a plan to me. And yes no harm in looking, maybe look for another set of heads, do the mods then perform a quick swap.
And with a 4.10 gear, higher compression, more cam and maybe an RPM intake should get you where you suggest you want to be.

 

The original trans behind a 455 would have been a TH400. If you're going to get a 200-4R, then go with the 455. Of course, that would be my answer even with the TH400.