BlackFox

Ok well to make this a short story and personal reasons, I called Woody back at Fordstrokers and cancelled my order with him for the 347 shortblock. So I found this website that has Eagle Shortblocks but they offer many different compressions. What is the big difference between them? Never really understood compression ratio and what it really does. Also is there major differences between KB, JE, and SRP pistons? From what research Ive found they just seem to be personal preference.

67mustang302

Compression can make the difference between running on pump fuel without issue and burning holes in your pistons. Or the difference between running boost or not on pump fuel. Basically more compression = more thermal efficiency = more power = higher octane needed = tune has to be more accurate. You need to know what your goal is, do you wanna use nitrous, turbo, supercharger, stay n/a, run on pump fuel, if so which octane etc. Cam also plays a factor in compression.

92GreyGT

Compression is a ratio of how much area is in the cylinder when the piston is at BDC and at TDC. Are you going to try and do the engine on your own or are you still going to buy an assembled short block?

BlackFox

Im going to buy the shortblock but like i said, i have no idea which compression to choose. I dont really plan on running a turbo, supercharger, or nos but you never know. Would be nice to have a motor that could withstand the upgrade with no issues. Thats really the main reason why im not sticking with the stock block and going all new.

92GreyGT

If you want to stay in a safe zone I would stay under 10:1. That will be a good all around number to stay at. If you stay with flat top pistons make sure the combustion chamber size is around 62cc or more.

BlackFox

so somthing like:

http://www.cnc-motorsports.com/produ...mp;CtgID=22981

or

http://www.cnc-motorsports.com/produ...mp;CtgID=22981

??

and is the Dart Iron Block the way to go with this set up?

BlackFox

By the way i will spend the extra money to get whats gonna work best for me in the long run. Im not trying to cut any short cuts. So spending 3,000.00 on a shortblock is not out of the question for me. Wanting to leave the option open for nos/blower/supercharger down the road.

92GreyGT

A Dart block is the way to go for ultimate strength but that is going to eat up most of that $3000. Those kits are fine but I am not a fan of hypereutectic pistons. That kit is kind of pricey for what you are getting. I know a lot of people on here don't like DSS but I have never had a problem with anything I have ever bought from them. Give them a call or send them an email for a price quote. How much power are you wanting to make?

http://www.dssracing.com/newxxr.htm

BlackFox

Well my main thing is im wanting Eagle parts. And for how much power? /shrug Would like to be in the nieghborhood of 350-400 n/a.

mjr46

you really need to decide if you are gonna run boost of any kind down the road....not a "I wanna leave the option open".....why?? cause a boosted motor needs low compression.....like 8.5 to 1 to run the most boost..even at 9 to 1 you can run good amounts of boost but not as much......so your full and final build goals need to be mapped out from the get go..and BTW......Woody can build you a low compression stroker...compression will be determined by the piston like flat top.....or dished in varying degrees off cc.........if your total hp goal is 400 hp then no need for a dart block...but if you wanna run550 hp and above constantly and push engine to max then a aftermarket block is reccommended