Strengths and weaknesses of the 351??? - Ford Forums - Mustang Forum, Ford Trucks, Ford Focus and Ford Cars

ScoopED · 10-31-2004, 18:25

Ok, I know these sorts of figures can be a bit dodgy, but I just need some sort of ballpark figures here.

What sort of horsepower can a late model 351W crank safely withstand? Does nitrideing give much of a gain?

What sort of horsepower can a late model 20thou over 351W block safely withstand? with and without girdle? I think the smaller 302's can cop 600hp or something...... hopefully 351 would be a bit more than that.

Thanks,
Mike

ebxr8240 · 10-31-2004, 21:33

5 Ltr Roller blocks over 450h.p and you are on shaky ground, with or without girdle...
351's are stronger and can go as high as 650 h.p..With four bolt conversion top ballance forged internals.Good tune.The sportsman maybe 100h.p more in 351.The Sportsman in 302 is hardly worth the trouble...

ScoopED · 10-31-2004, 22:19

Ok, I didn't think it was worth going to a sportsman block.

I am finally on the road to my conversion.

Just having real problems finding a 351W Roller block.

Specs will be, 351W Roller (obviously) Forged low comp pistons, H beam rods, Alloy heads, nice cam, stud girdle, EFI, aftermarket ECU, vortech V2 at 7-10psi intercooled.

Shouldnt get over 650hp at engine with that combo i wouldnt imagine. I'm guessing maybe 550hp max which is the goal, approx 300rwkw. Sound about right with the estimated power figure???????

347stroker · 11-01-2004, 00:44

Blocks with D4 casting would be the best to look for, a bit thicker in the pan rails, and down low in the block, and converting it to roller is a no brainer.....
Good luck, sounds great.

ScoopED · 11-01-2004, 01:03

What sort of work is required to convert a block to a roller. (excuse the ignorance).

Mike

ebxr8240 · 11-01-2004, 04:17

You either use a small base circle cam and use std rollers or use aftermarket valve gear..The roller cam follower [lifter] is too long for non roller block, as the roller block had longer lifter bores and if you use roller lifters in flat tappet block they lift above the oil feed gallery...The 351 roller block out in 95 so ther won't be many around..Btw the Lighning [s/c] F150 was flat tappet..