5.0kid

I know the 302's are said to be safe till about 450hp but what about 351w i know the increased deck height helps because its got more material in the main webs and elsewhere. But what is the safe hp level on a factory 351w before they start to crack?

bighungrymatt

what year block? I would say 650 would be safe on a 69-70 block. how much power is your goal? might want to think about a dart block

greenstreak9205

700 is the red zone(ish) for the windsors. I wouldn't wanna push it much further than that. Can it hold past that...sure. But how reliable would it be at that point?

5.0kid

its a 89 out of a bronco. I wasLooking at dart blocks but they are little expensive right now with the way the economy is. so some where in the 550-650 range? Does it start to get main cap walk after 700hp?

woodsy

cap walk will set in around the 650-700 range, rpm is really the killer. Watch main bearing clearances first and foremost with the large 3 inch mains, MINIMUM of .0027-.0030 personally.

5.0kid

If i keep it under 6500 will it be safe to that power level. along with a good set of forged internals. Along with main and valley girdles. Does stroking it out to like a 393 or 408 make a difference in the reliablity of the block woodsy?

woodsy

Main girdle and Valley girdle wont help you, stud the mains, keep it below 6500, plenty of main bearing clearance and 650 it will live. Can make 600-650 with a 408 relatively easy if you do things correct. 500 on a 408 is simple. Last plenty long

5.0kid

well im looking to have a blower on it? sounds to mee like i just need to save for a dart block

stang8689

Can't go wrong with the Dart block, atleast you know your safe

5.0kid

is there another cheaper alternative to a Dart or World Products block? Are the FRPP 351 blocks any good?