What is the least expensive 393 build for a carbed motor to go into a 4X4. I understand you have to buy a crank but can use factory rods & 302 pistons. what balancer & flex plate? What torque & hp out of factory heads & factory 4bbl intake? Thanks

 

stoke heads and intake will limit your output for sure. yes you will run the 393 crank, 5.8 rods and 302 pistons. the block will need clearanced possibly. if you can spend some money anywhere it should be done on the heads and cam. others will chim in on combo's to run. there was a guy on here that did a basic 393 and puts out some great torque numbers but the hp was right at 300 or just below on hp.

 

I built a basic 393 using stock parts (except for the crank of course). I wanted the extra torque for a work truck and I needed to stay in budget. If your budget allows, go with what K'burns said and spend it in the intake and heads. You don't need a high dollar crank, but you do need a good crank. I would stay away from the Ebay bargains. A lot of them require work before you use them, so you might as well buy a good piece to begin with. Spend a little more and buy one from a known crank supplier. One thing I had to deal with was compression ratio. I ran a cam with a fairly early intake closing to bring in more bottom. I had to work a little to get my DCR right, because I needed this motor to run on 87 in the hot desert. Keep tabs on this if you are building a low rpm, torque motor. I ended up using 69 cc heads and had to CNC the KB pistons to open up the dish. I didn't need to clearance the block, but had to pay close attention to balance. This motor is not a bolt together as some may lead. You need to check everything, then check it again. The end results met my needs to a T. I have noticeable torque increase off idle to about 4500. Perfect for my needs when pulling over 8000 away from a light with 3.55 gears. For my application and budget, I am quite satisfied and feel it was well worth the extra expense and work. It runs well on 87 in 110 degree heat with not a single ping. If your budget allows, anything to make a 393 breath better will pay dividends. If you have the money, spend it there.

 

Thanks for the replies. I may just build a hopped up 351M or 400. It seems the displacement & better heads are already there. Thanks again

 

to gain much from those motors requires lots of head work, better intake and carb and a cam upgrade as well. not to mention the 351m and 400 use the big block bolt pattern so a different tranny would be required compared to a small block bolt pattern tranny.

 

do the 393 for sure