Found the knock

A guy had given me a 283 short block and my son had pulled a 305 with a knock from a camaro he had bought and has been in the way for sometime.So I plan to mate the two and this is from the 305 bottom end.
http://youtu.be/KPoWQsTO_ig

must have been knocking for a few miles . Does the 283 have the soft valve seats ? or is that just the 327 ? I was told one of them had it and you needed to get them replaced or they wouldnt last . because of our unleaded gas we have now ..I dont know

Yankee Transplant said:

must have been knocking for a few miles . Does the 283 have the soft valve seats ? or is that just the 327 ? I was told one of them had it and you needed to get them replaced or they wouldnt last . because of our unleaded gas we have now ..I dont know

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Both........all pre 75 engines had softer valve seats, lead in the fuel used to be used back then to lubricate them.

How do you plan to mate the 2? Small journal 283 crank in a 305 block? Bore it .014 and have a 265.

Willowbilly3 said:

How do you plan to mate the 2? Small journal 283 crank in a 305 block? Bore it .014 and have a 265.

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Take the good bottom end(283) and put on good top end(305) vortec heads and intake.

casting#14102187.

sneakysnake said:

Take the good bottom end(283) and put on good top end(305) vortec heads and intake.

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That should work. You might want to check the cc on those heads, most 305s had some real small chambers and you might be conjuring up a compression ratio that you can't live with. The 305 HO heads are some good flowing heads.

sneakysnake said:

casting#14102187.

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Those are centerbolt heads, but not vortec, they are actually TBI. Lots of people see the valve covers and make that mistake. But that's a pretty good combo, I also like using the 305 heads on 307 lower end, makes a pretty decent little motor.

Plaintoast said:

Those are centerbolt heads, but not vortec, they are actually TBI. Lots of people see the valve covers and make that mistake. But that's a pretty good combo, I also like using the 305 heads on 307 lower end, makes a pretty decent little motor.

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Thanks, not trying to build a hot motor as much as for the price of a gasket kit have a complete engine and a little more room in my shop.lol

I had a set of bigger valves put in a set of the small combustion chamber 305 heads and ran them on a 327 stock bottom end. With the cam I had in (spare parts) it, it had zero bottom end but would fly once in the rpms a little. I used it as a trailer motor for years. Cheap horse power for sure.

i put a set of 305 ho heads on a 307 for a friend. i talked him into letting me port and port match the heads. we added a 270º duration cam and the other usual add on's. it was a sponky little motor. sneaky i would at least try to port match. that way he could add add on' later. even better teach him how to do it.