USMCrebel

Im thinking on a 331, but 347 is aweful tempting......i dont really know much about the specs on these, i've seen numbers all over the board, what is a good guesstimate
331= 375hp
------400hp

347=400hp
------425hp

which one and why?

ldollar

I am sure some people will tell you to steer away from the 347. Depending on your needs, I would not write it off too quickly. If you are going to shell out the cash to do it right (and let the pros build, install, balance it...) you will be glad you did. Mine was built for me before I bought the car. It was about $8k but the torque it rediculous. I absolutely love this engine. Due to the extra wear from the longer stroke, you cannot expect the engine to last as long as a stock 302. But I think it is reasonable to expect to get 90-100k miles out of it if it is maintained very well and not driven into the ground. Mine has abot 19k miles on it and is pulling HARD. love it.

USMCrebel

Well the pro's arent going to do it i am, im trying to learn everything i can about them, installing them working them.....everything. It's my goal to own a performance shop here in town within the next 5-10 years. with a specialty on mustang of course

superdavid

I would go with a 331, just to be on the safe side. You can take a 315w out to 427 or i guess even 454, but I only took mine to 408. Its better to have a 331 that runs good than a 347 thats scattered over half an acre....

ldollar

well it sounds like you are on the right track in opening your shop. I dont have the time, equipment, patience, or know-how to do it myself. I just want to drive, thats all.

Starfury

Depends on what you're looking for in an engine. If you want the most torque you can get and can live with a shorter engine lifespan, definitely go for the 347. They're perfect for street/strip cars. But if you're building an engine for more of a daily driver, 331 all the way. It'll last longer and produce almost as much torque as a 347, and be slightly more fuel efficient.

I've got a 331 in my 67fb and I absolutely love it. With Rhoads lifters and a Comp Cams 280H it pulls from 2k all the way to 6k+.

JMD

Check out these from Summit,, ballanced kits starting at $1,000.00,,,, all of these are 5.4" Connecting rods,,, for a not bad rod ratio....

This will mean that the oil ring will probably pass through the pin area of the piston,,,, but everything is a comprimise anyway.... In our 408, we elected to go with the longer rod and have the oil ring go through the pin area,,, 75 miles on it now.... so far so good...

If I were to stroke a 302,, I would go 347.....

http://store.summitracing.com/egnsea...=sku&RC=10

Starfury

Iwent witha long-rod (5.4")331 with the pin bore intersecting the oil ring, mostly for the extra low-end grunt. No noticeable oil burn so far Most decent pistons nowhave provisions to help prevent oil consumption. My KB hypereutectics have a locator pin in the oil ring race and special oil rings to keep oil from reaching the chamber. I've seen other pistons that actually move the rings up above the wrist pin bore, although this makes for a VERY short piston, too short for my liking.

USMCrebel

well, i want to set my goals high, so i eventually get good enough that ford would have a thought of hey maybe we could use something of theirs......if they just have the thought thats good enough for me

now i can wake up and just make it good around here.

groho

I'm lookin at the same for my 66. I've spoke with several machine shops, and all have indicated the 347 requires more machine work on the block to clear the end caps, but definately has punch when it's done. 331 is a more reliable engine combo for the street.I'd suggest having the short block machined, built,balanced and assembled by a pro. If they're already doing the machine work and balancing, what the heck is a few extra dollars to put it together. The rest: heads, cam, intake, carb,distr, you can easily do yourself. The hardest part isfinding a GOOD, DEPENDABLE machinist who won't cut corners.