Comp XE268 - O/T, Brand X!
I just sold my 69 lemans two years ago,I still love pontiacs (actually all brands of muscle cars) but its fun to run 12s with a 3.42 gear and 29 in. tire.Anyway I would run the xe268 but imo even better would be the lunati voodoo 268-just a bit more lift.One thing you will notice is 400s have a piss poor deck height,a 400 I rebuilt had some cast repalcements and they were .044 in the hole,now combine that with the small chamber heads and it still was only 8.8 to one so you will need to do your reaearch on pistons.Check out theae guys http://www.pacificperformanceracing.com/ Ken is really cool and this website is great for specific searches to get info http://forums.performanceyears.com/forums/ .As far as the rods they will be fine to 6k with good bolts-although the rods are not great the stock bolts are 90% of the problem.I built several pontiac engines and the last one was a 400 to put in the lemans to sale,it had 8.8 compression,#16 heads that I ported,comp xe 274,stock rockers with crane adjustable nuts,1 5/8 headers with 3in ex.,rpm intake,750 holley,t400 2,800 stall (flash) and 3.42 gears with 29 in. mickey et streets (was set up for a 455 before).This combo ran 12.70s at 107 shifting at 5,500 in a 3700lb. car so your build should meet his desires.I would run a mild stall,problem is pontiacs have so much low end you really need a custom stall built by someone who knows what their doing or you will get too much slippage on the top end,I did find that a reman ls6 12in. chevy convertor works very well,you can get them at any trans shop ect and I paid around $75.It is factory rated as a higher stall and I found it to stall right around 2k on the brake-perfect for a street build-but it has very tight once you give it throttle,I ran a couple ofthese in my car before having a custom 11in. built.Good luck on the build and heres a pic of my old poncho.
I just sold my 69 lemans two years ago,I still love pontiacs (actually all brands of muscle cars) but its fun to run 12s with a 3.42 gear and 29 in. tire.Anyway I would run the xe268 but imo even better would be the lunati voodoo 268-just a bit more lift.One thing you will notice is 400s have a piss poor deck height,a 400 I rebuilt had some cast repalcements and they were .044 in the hole,now combine that with the small chamber heads and it still was only 8.8 to one so you will need to do your reaearch on pistons.Check out theae guys http://www.pacificperformanceracing.com/ Ken is really cool and this website is great for specific searches to get info http://forums.performanceyears.com/forums/ .As far as the rods they will be fine to 6k with good bolts-although the rods are not great the stock bolts are 90% of the problem.I built several pontiac engines and the last one was a 400 to put in the lemans to sale,it had 8.8 compression,#16 heads that I ported,comp xe 274,stock rockers with crane adjustable nuts,1 5/8 headers with 3in ex.,rpm intake,750 holley,t400 2,800 stall (flash) and 3.42 gears with 29 in. mickey et streets (was set up for a 455 before).This combo ran 12.70s at 107 shifting at 5,500 in a 3700lb. car so your build should meet his desires.I would run a mild stall,problem is pontiacs have so much low end you really need a custom stall built by someone who knows what their doing or you will get too much slippage on the top end,I did find that a reman ls6 12in. chevy convertor works very well,you can get them at any trans shop ect and I paid around $75.It is factory rated as a higher stall and I found it to stall right around 2k on the brake-perfect for a street build-but it has very tight once you give it throttle,I ran a couple ofthese in my car before having a custom 11in. built.Good luck on the build and heres a pic of my old poncho.