When you click on links to various merchants on this site and make a purchase, this can result in this site earning a commission. Affiliate programs and affiliations include, but are not limited to, the eBay Partner Network.
Well it's been a while since ive been on here!Well im back,and need some help.I have a 79 Bronco with a 400/C6/NP205 9"rear D44 locked front.Im getting into mud racing,and I need to wake up my 400!I have a basic stock rebuilt 400 with a weiland intake,and a 600cfm Carter AFB comp series,and 8.8mm msd wire's,and msd blaster II coil.Im not getting enough throtle responce when it's time to go.The msd 6A made a real noticable differance but I know the motor has more snot then what im getting.Where do I start in getting more throtle responce?Bigger cam,head's?I also have headre's with 2.5" duall exhuast into 40 series flowmaster's.I have 3:54 gear ratio.Any help would be great??
I'm not an expert in mudding but 3:50's seem a little tall to me, I'm thinking you should be looking at something in the 4:56's. The 400's respond just like any other SBF... they like to breathe and cams with lots of lift!
you need to upgrade cam, increase the compression ratio to 9.5 or more and get the heads worked over a bunch. get a 650-700cfm carb. the gear ratio is also not helping you at all. i didnt see you mention what size tires your running so if you can provide that it will help figure out what gears to run.
also with your exhaust i would run an H pipe or an X pipe to help scavenging.
33x13.50x15 in rear and 33x10.50x15 in the front.I was afraid if I wen't higher in gear it would just spin when a hit the throtle?There is a 1980 Bronco that whoop's me and he has a 302 with c6 and 205,and he has same tire's but he spank's me.Im doing a 5.50sec. in the 150ft.
also remember those 302's can spin way up in the rpm range and still make power. the 400 falls flat im sure after 3500 rpms and wont rev past 5grand in stock form. its also hard to say what all he has done to the motor/gearing etc. weight could also be a factor. if you can take off your hard top you will save a couple hundred pounds right there.
One other question is my 1979 F250 Supercab4x4 dually has a 460/NP435/NP205 with 3:73's,and WoW what a differance in truck's.My dually Supercab will eat my bronco all day long!There isn't much other then a edebroke carb and intake done to it either.I wish I could get my 400m in Bronco to turn on like the 460ci in my Supercab.Does 60 cubic inch's make that much of a differance??Or is my carb. on the 400m sick?I know for fact timing is dead on in both.