[Nice 5.0]

I've been thinking about building a 351w short block and I keep hearing about the older blocks being stronger than the newer ones. My question is how much power have you guys seen on the newer ones. And for the moment i'm going to have to run my world product windsor jr. heads with a 58cc combustion chamber. How much compression would I be looking at with a flat top piston.

[TurboLX]

i have 1986 F250 351w in my 87' Hatch and its holding pretty good at 721hp on low boost

[trueblue01]

Using standard bore, 0.00" deck, 4 cc valve relief, .042 head gaskets 58cc chambers will net 11.2-1 compression

[Nice 5.0]

Originally Posted by trueblue01 Using standard bore, 0.00" deck, 4 cc valve relief, .042 head gaskets 58cc chambers will net 11.2-1 compression

Is that to much compression for a street car. I want to be able to run pump gas. Would I need a set of dished pistons to get it down to around 10.5-1

[trueblue01]

Depends on the dish size but with the proper timing and high test 11.2 should be streetable.

[86gtconvert]

standerd deck,and standard bore,flats around 8-9.1 depends on if its stock pistons or not jrs are 58cc heads 1.94-1.6 valves .cam duration has a hand in itto cuz of how long valves are open

[JBIGBOOTSY]

Originally Posted by trueblue01 Using standard bore, 0.00" deck, 4 cc valve relief, .042 head gaskets 58cc chambers will net 11.2-1 compression

He has .020 xtra on the deck.

[trueblue01]

+ .020 will drop the cr to around 10.66 to 1. Remember this the static cr.

[ryans88gt]

Originally Posted by trueblue01 Using standard bore, 0.00" deck, 4 cc valve relief, .042 head gaskets 58cc chambers will net 11.2-1 compression

Did you factor in piston to bore volume and cylinder chamfer? That can be significant especially for forged pistons.