80cjinnc Well I finished my 401 and made one race to test and tune before the end of the season. I was really happy with it and figured with a little tweeking here and there I would be set for this summer. That was until yesterday, I heard the track I was wanting to start going to have made a new rule saying that 390 and down is a small block but a 401 is a big block and has to run in that class? I guess a 400 Chevy should also be a big block then right? Anyway I am now looking at taking the 401 out and building a 360 or 390, any ideas? I have heard that you can take a 360 and fit it with alot of different parts and build them up pretty good, I will need to pull 14 inches of vac. at 800 RPM to stay in my current class other than that and of course on nitrous and on carb. I am thinking of building the 360 because if they change the rule again next year a 390 really did not come in a CJ but a 360 did. Any Ideas?????
donwag "390 really did not come in a CJ but a 360 did. " Don't think so. CJ's never came with a factory 360. They did come wth a factory 304.
80cjinnc Well thats good to know, I thought they came in some cj8's but I guess not. Well I will just have to hope they stick with rules they have now then anything but a 401 is ok. Thanks for the info.
RAMBLINFSJ duckbone wroteGrind off the 401 and weld you a 390 bead on it. That exactly what I was thinking. :t:
tufcj Take a 360 block, bore it to 4.165" and use the 401 parts. Nobody will know the difference unless they tear it down and measure. It ain't cheatin' unless you get caught. Bob tufcj
tarior First off, get rid of that Fram filter! :mrgreen: Second, if you grind off the 401, how are they going to know? If they don't do tear downs, then no worries. I highly doubt that anybody on the tech crew knows jack diddly sh!t about AMCs.
80cjinnc Thanks for all the ideas guys. I have not made up my mind on what to do yet, I am going to miss the first race next weekend due to work and it looks like I will still be on night shift next month and miss the second race plus no time to do anything to the Jeep. I have been thinking really crazy but I just might leave it the way it is and let someone else enjoy it, just have no time right now and I hate having it just sit there like it does most of the time. I did take it to work the other night and then put it right back in the garage.....We all need to figure out how to work less and play more, if I figure this out I will let you know..
AMX69PHATTY A 360 block bored .030 over to 4.110 bore with new pistons and your existing 401 crank and rods in that 360 block will make 390 cubic inches 401 crank 3.68 stroke, 1.840 throw + 5.858 rods = 7.698 9.208 360 deck ht - 7.698 = 1.51 compression height for 0.000 deck clearance Stock 401 pistons are 1.508 comp ht Stock 360 pistons are 1.601 compt ht aftermarket 360's are 1.580 - 1.570 comp ht usually. So a .030 over 360 block with 401 crank and rods is a 390 and legal right ? :wink:
80cjinnc Yea, that would be legal and is a great option for me. All they look at is the side of the block and the number there, so that would just be a 360 to them. Thanks
