302 block question?

Want to build a 347 stroker from a 302 production block. The engine will be used for 98% street use, couple times at the 1/4 mile, and a time or two at the road course. The application is for an AC Cobra replica (2400#) with a T-5wc transmission. Want the engine to make mid 400 HP with carb spinning no more than 6500 RPM's, then a 100 HP shot of N20 on occasion. My question is...will a 5.0 roller block be OK for this? or do I need to find the 302 Mexican block? other suggestions?

Some say the 5.0 block is thicker/stronger, but either or will work. Some good AFR heads will definitely work nicely. Roller cams are the ticket but you can still achieve 400+ HP with a hydraulic cam too.

A regular 289 (be careful it's not for a five bolt bellhousing) or early 302 block will be stronger than the later 5.0L thin casting block. Only down side I can think of is that you will need link bar lifters for a roller cam.

Don't bother looking for an Mexican block , My buddy payed big bucks for one, once the main caps were removed the weight was within a few ounces of the stock 302 block . If there is any beefing it should weigh more .

The mexican block isn't necessarily heavier, it has a higher Nickel content that makes it stronger pound for pound.. The only downside aside from its rarity and cost, is the lack of factory roller. Oh and you never know the history of the block unless you have it checked out before you buy.

Having said that , a late model Roller will handle 400 to 500 Hp comfortably with a Good tune. Detonation under max power in the 500 hp range seems to be the major culprit of block splitting.

Have the whole reciprocating assy balanced well, de-burr or Roll the sharp edges of the block well with some sanding rolls (except the machined area of the mains ) and you'll be in great shape.

On a separate note.. I'm always curious if anyone has ever done the Cryo treatment on a 5.0 roller block to see if they withstood any more HP reliably? Supposed to be a hot ticket strength wise, however costly.
Have Fun!

I stroked my 1970 Mustang 302 block to 347, no problem so far. I've never had it dynoed, so I'm not sure how much hp it's making. I run mid 12's on all motor. Compression ratio is 10.1:1, AFR 185 heads, QFT 750 carb, RPM airgap intake, MSD 6AL ignition, Cal-tracs, XE274H Comp cam. Yata, Yata, Yata My rotating assembly is Eagle. Good luck!

Barry

My block is a 1972 302 block stroked to 347 cubic inches. No problems here either. Compression 11:1, World Product Jr heads modified, 650 BG VS carb, Victor Jr intake, Davis DUI igntion, XE284H cam. No track times as of yet, but sitting somewhere between 450-475HP.

thanks for the feedback...anyone with 5.0 stroker feedback?

They made the 5.0 blocks lighter - not weaker. Several turbo and one supercharged 5.0 around here running ~450-600+hp with no issues on prepared stock blocks. The 600+ engine even uses nitrous, but only to spool the turbo quickly off the line. 500 on the bottle should be reliable NA/nitrous with a race prepped block. And to repeat what 71hotrodpinto said... with a good tune. Can't stress that enough. The best parts in the world are at the mercy of tuning and that takes a bit of time and money. Think of it as better performance with a cheap insurance bonus.

David

I agree with PSIG, the newer blocks are lighter, strong and reliable. I don't know for sure, but have read that the higher nickle content in Mexican blocks was a myth that has been disproved, they are just heavier. The 69-72 blocks are supposed to have a higher nickle content as well, or so it's been rumored. I think any block will work, but the late '74 thru early '84 are the worst blocks Ford ever made. So -before or after, but I give the nod to after for weight, the roller cam and 1 pc. rear main seal.Just M.O.