[joie383]

Need suggestions I am going to build up a small block chevy 400 I will drive the truck its going in on the street but would like to kick but in the 4x4 mud drags we go to thats why I chose the 400 they move us up in class by what mods they can spot.So heres the plan stock lower end which will limit the rpm's to 5,500 max.I was going to go all out and build it a little on the wiled side but a friend talked me out of it so heres the parts list.vorteck heads 64cc chambers 1.94 intake 1.5 exhaust valves.Vorteck performer intake.stage 3 qjet from jet performance,HEI with 50,000 volt coil and new module,1.5:1 roller rockers,crane Saturday night special cam with 470" lift 280* duration 230*@0.050 and a 106 LSA,A cheep pair of headers,2.5" exhaust 2,000 RPM stall,Street strip shift kit and 3.73 gears with 36" boggers.I want to keep the visual mods to only 3 any more and I won't be able to stay in stock class any one halve a better idea.

[Max Keith]

Other than the cam, which is in my opinion a bit more than you need for camshaft with your setup. I dont think you would be happy with it. If you would drop back about 10 degrees on duration @.050, you would see better bottom end, and wont need to go to a higher stall torque converter. I think the Crane PowerMax H-272 or H-278 would be more in line with what you are needing.

[joie383]

what is the duration at .050 for the cams.I did the math my self and figured out thet if the motor had 8.38:1 compreshion with a 78cc head thet when I switch to a 64cc head my compreshion will be 9.79:1 and if I use a 305 head with a 58cc chamber it will be 10.54:1.We do use 130 octain airport fuel when we race and I would rather be good on the track then the street.As long as it will drive I will drive it around town even if it runs a little ruff send me the specks on the cams I know there duel patern and that might be beter.The stall is a must and a little on the low side I am drag racing thrugh mud on the weak ends and the cam I chose ses its good for 2,500-5,500 RPM the tracks are around 300 feet but with 1.5 and a flat torque curve is what I am after dose this change any thange.what about using rhoads lifters to get back my low end they say 20-30" les lift at idle and 10-15* les duration and restores it at 2,500-3,500 RPM so I would halve a V Teck efect like a honda.

[DoubleVision]

I don`t think the cam presents any problems, we`ve ran them bigger in a 4x4 with a 400 small block, and you could hardly tell it had a bigger cam in it since 400`s take bigger cams well. The vortec heads will work fine, but make sure you have the steam holes drilled in the head deck or you`ll have nothing but endless problems with it overheating. You may want to go with a looser stall converter, since in mud racing as we used to do, the launch is very important. We learned by watching others, you can`t win with wide tires on a full weight street truck, we always ran the narrowest buckshots we could find around 37 inches tall and we have a few 1st place trophy`s to show for our efforts. I would also consider having new rod bolts added if you plan to stick with the stock 5.565 jobs. Tune it right, added a X pipe to the exhaust, stall it in low range release the brake and hold on.
Also, make sure you have the correct balancer and flexplate for the 400 small block. you won`t need rhoads lifters, the truck will have plenty of low end power, as this is what 400`s excel at. If you haven`t already, maybe look into comp`s 4x4 cams, as these are made just for that purpose.

[joie383]

I would like to use 38.5 x 11.5 x 16 boggers my friend is using them and has a lot of trophies but he races in modified class and sum places will pout me in his class with those tires and rite now he makes 450HP shifts at 6,500 with a 3000RPM stall and a trans brake so I do not wan't to be in his class so I half to settle with 35 or 36" boggers and I am not sure how narrow they com I think 12.5 Can I drill the steam holes my self? I halve a drill press.How far do I drill in?Till I hit a water passage rite?

[DoubleVision]

Have a machine shop drill the holes, it don`t cost much and they make a quick job of it, some of the holes have to be angle drilled.
Why I suggest narrow tires is because when we ran swamper 38`s that were 12.5 inches wide, they tended to "ski" which is when the front end would glide across the top of the mud, giving no steering, when the truck`s weight would shift back to the front end the tires would sink back into the mud and the truck would go from hauling a** to almost a crawl. this is the reason for running a narrow tire on a lower horsepower heavier weight truck in a different class. if the mud has some depth you`ll see what I mean, but if it`s the "mud so shallow a go cart can ride through it" then just stick with what you have, as that`s not really mud racing, it`s mud drag racing against the clock.