I'm in the process of building my 455 from a 68 Toro. Had to get a .030 overbore due to wear and a -10 grind on the crank. I understand this was a hi compression motor and after checking, this has the bigger valves in the C heads. My question is what would the installation of a deeper dish piston due to the performance of this motor? The original pistons have a very slight dish. The other changes will be Edelbrock Performer intake, headers, roller rockers, and a mild cam. I'm gonna rebuild the original Q-jet too. Asking because a friend can get me low compression pistions VERY cheap.

 

It would decrease your performance by lowering your compression. Replace with the same compression pistons as the stock ones. Go with forged if you can afford it they are the best, there are a number of brands to choose from. Shop around and check evel bay as well

 

Definitely don't go to the lower compression pistions. Even if they are cheaper through your buddy. You can usually get a great deal on a rebuild kit with forged pistons from Summit, Jegs, Kanter, or Fusicks. I suggest the TRW L2323F pistons.

 

Compression is a wonderful thing, it makes both power and torque. But, those high comp engines were around back when you could buy 102 octane fuel. So, plan your build carefully so that you have the best compression ratio and camshaft to match your gear and vehicle weight. "Performance" is a subjective term, but I agree that more is better, as long as it isn't too much. You'll remember the awesome torque and power a lot longer than you will remember the $300 you saved.

EDIT, just ran the numbers real quick. The 2323s have an 18 cc dish, so depending on the variable the Cr will be 9.5-9.8, which is perfect for a street car. Match that with a cam in the 220 @ .050 neighborhood and you should have a nice runner.

 

Thanks for all your feedback guys. The cam i was looking at is Comp Cams and is 211@.050. I'm using the Comp Cams roller rockers cause they were thrown in with the engine when I bought it. I didn't think extra lift would hurt. I have TH400 with a shift kit and a posi rear (not sure what gears yet) lifted from a Cutlass in a junkyard. I am looking to keep some strong torque while building a reliable motor.

 

cam sounds tiny might want to re-think that one

 

I know first hand what low compression pistons will do to the performance of your engine. oops. I've made a lot of mistakes while learning this stuff and I'm sure I'll make a few more, but I will never make that one again.

 

Is this the cam?
http://www.compcams.com/Cam_Specs/Ca...csid=1179&sb=2

If so, I agree with Gearheads, if your compression ends up being close to 10 to 1, that is a pretty mild cam for a 461.