I have a chance to buy a ZZ502/502HP that dropped a valve, the price is good but what can you guys tell me about the block, crank, pistons,ect. I don't have to buy this, I have a pretty good running 427 but the price on this one is very reasonable. I would be getting a complete motor from carb to pan and what they tell me is the cylinder looks good that dropped the valve.
Can these blocks hold 600 to 700 hp on a motor that would be bracket raced on a regular basis. Any input on this motor would be a big help before I get to involved with this project.

Thanks Bill T

Hey, Billy
Been busy at work didnt get a chance to answer your email, so...
Yea they can handle plenty power, blocks are good for around 1000hp, with the rear webbing being the weakest. Steel crank is good, and are 1pc rear seal. Should have 7/16" rods. But you may have to stick some pistons in it, unless the heads have small chambers to get the comp. up. I'd buy it if the price is good. Dropped valves are a common problem with them, cheap locks I guess - Fix that before you get it running.

Rafal,
Thanks for the input, the motor is a stock ZZ502 aluminum head version. The heads are the same as the edlebrock I guess with the intake valve being a 1.25 verse the edelbrock 1.188.
Are you running the stock rods and pistons in yours? I know that your motor is a low compression version of the 502. I may give you a call tonight and asked you a few more questions.

The aluminun oval ports sport 2.250 intakes and 1.88 exhausts.I do believe the static CR is 9.6/1.The hydraulic cam goes into float early.No suprise it dropped a valve.Rev limit with this shaft and springs should be under 6 grand.

thanks Fatblock,
My mistake on the valve sizes, I did read that the rpm limit was 5800 or something like that. What is the block bow tie or gen 6?

That zz502 would be generation V with no fuel pump boss and no adjustable valve train.Stacked from the factory to work with the 524/544 roller hydraulic .

did you get a chance to inspect it? Dropped valve is a pretty big deal...everything may be trashed.

ZZ502 is a Gen VI block. Has adjustable valvetrain. The iron head 454/502 motors dont have adjustable valvetrains

Gen 6 block is not a bowtie, but is good. They come with a steel crank and 7/16" steel rods. just the pistons suck (around 8.5 comp w/ open chamber).
I just got a 502 block and stuck some stock junk I had layin around in it, so it has a stock cast crank, stock 3/8" rods. I bought Lunati 10:1 pistons, and got a decent cam.

67RS502
How much duration are you running with your cam? I know that the one I have in the car now is a little smaller than a big motor would like but its what I have now. The heads are 110 semi open combustion chambers, I will check this out tomorrow if all goes as planned.

Sideways
Its a racing buddy of mines dads motor, he said that he checked the cylinder and it looked good, he didn't however say anything about the head.

Thanks all for the replies.

Thanks Sideways.I was told the ZZ502 was non adjustable.They have screwed in 7/16th studs?