How can you tell the difference between a 5.0 tpi and a 5.7 tpi engine? I know the 305 '86 and prior the valve cover have 4 bolts on the outside corners. The 305 '87 and up have the 4 bolts in the center of the valve covers. Don't the 350's have the 4 center bolts too?

How can you really tell the motor is actually a Crate 350tpi?

I looked at a car, an '85 Iroc, auto. The guy said the motor is a Crate 350tpi motor. How can I really tell it's a Crate 350tpi and not a re-built 305tpi? Are there markings on the motor that I can tell the difference?

Thanks,
Tim

 

Check the casting numbers on the block behind the driver side head.

 

if it is a "crate motor" as for the sales invoice.

you call tell a motor size by the casting number on it back by the fire wall on the passager side. The last 3 casting numbers on a 305 is 627, 350 is 638. my 305 does have 638 by the timing cover so don't go by that. The newer blocks came with the size cast in them also, on the drivers side, ie: 5.0L or 5.7L. these are hard to see in the car. is you get the casting number off the back of the block, you can go to mortec.com and look the up. hope that helps.

 

Not sure about the crate engines but newer factory engines actually have the 5.0L, or 5.7L stamped in the block behind the drivers side head. Use an inspection mirror. However, I would also take the advice of 85gulstrandTA and ask to see the sales invoice.

 

My crate engine had a tag on it where the fuel pump block-off plate goes, and it states what size block it was and if it's been bored out. (I never noticed until I pulled the engine...?)
Otherwise checking the rear of the block on the driver side will tell you like mentioned above.....

 

Thanks guys...