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View Full Version : small block and torque?


muddstopper
03-01-2008, 12:45 PM
I thought i would throw this out there just for opinions.
I have a 95-3500 dually that has outlived its 6.5 diesel engine. I dont really want to junk the truck as I have already put new rear and frontends under it and the body and interior are in decent shape. And I dont want to install another 6.5. Might try a cummins tho if I can find a cheap one. I thought that since my new F450 was getting such poor fuel mielage, I would throw a small block in the 3500 for towing my smaller trailers around. My thoughts are to just rebuild a 350 I have setting in the shop but then got to thinking how to make it a better puller. One thing leads to another, you know how it is. Anyway, if you where going to build a 350 engine for a tow vehicle, what performace parts would you consider. My thoughts are maybe a strokerr crank and 6in rods using heavy pistons, and lower compression ratio (8.5-9:1) for cheap pump gas. That should deliver better lowend torque and I aint interested in high rpms. Then top the engine off with the vortec heads and maybe a rail injection system and hei distributor. Which heads would you look for and remember I aint racing. I also am considering a turbo with low boost. I definately will be loseing the computer off the diesel and would like to keep the installation computer friendly. I have also considere the bigblock, but I dont have one lieing around and those I have found are pretty expensive, late model and will require a bunch of additional electronics I dont want to fool with. Either engine should bolt up to my current flywheel and bellhousing after haveing the flywheel balanced of course. Motor mounts aint a problem, junk yard is full of them. \

Anyway, lets see what you lawn guys can come up with.

IA_James
03-01-2008, 02:08 PM
Edelbrock #3702 or Isky 210252/257, stock ratio rocker arms, new lifters (the Isky is a roller I think, if so you'll need new pushrods), Edelbrock Performer (not Performer RPM!), carb of your choice (Rochester or Edelbrock), set of Vortec heads, and you'll have a truck that will pull stumps. The Chevy Vortec heads are pretty well the gold standard, you have to spend a pile of money to do much better. I'd keep compression at 9.0 or lower, and not mess with a turbo. You start getting into having fire rings and studs for heads, need an intercooler, extra plumbing, weird jetting, all sorts of stuff. A stock HEI set up pretty well quits after about 4500 rpm, so keep that in mind with your cam selection. You may wind up needing a computer to control your transmission (shift points and such), I'm not real sure.

muddstopper
03-01-2008, 02:43 PM
Trucks a manual so not worried about shifting. 4500 rpms will do fine for towing I would think. Am curious as to why a carb instead of using fuel injection? Holley and Eldebrock both make fuel injection kits for older model conversions. I assume the part numbers where for camshafts?? I agree about the vortec heads, just wondering if I should go with the larger valve heads or the smaller valve ones, I cant remember the numbers off the top of my head. I think both have the same CC combustion chamber.

Sydenstricker Landscaping
03-01-2008, 02:43 PM
Dont forget to get a decent cam in that thing too. I put a .488"intake/.502" exhaust cam in my old chevy 350, 1982, pre vortec, some good headers, gear drive timing...for that supercharger whine, lol, flowmaster duals, Hi voltage ignition system, edelbrock carb, forgot the exact size, and an edelbrock performer intake. That truck had so much torque, it tweaked the frame a little bit and would stuff you into the seat, almost thru the back window. Make sure any cam/intake/carb combo are recommended for each other and have like a 1500-6500 rpm range. The lower the range, the better low end you have. Even a stock 350 would have not an issue pulling small trailers around.

IA_James
03-01-2008, 04:19 PM
Trucks a manual so not worried about shifting. 4500 rpms will do fine for towing I would think. Am curious as to why a carb instead of using fuel injection? Holley and Eldebrock both make fuel injection kits for older model conversions. I assume the part numbers where for camshafts?? I agree about the vortec heads, just wondering if I should go with the larger valve heads or the smaller valve ones, I cant remember the numbers off the top of my head. I think both have the same CC combustion chamber.

I'd run a carb simply for ease of installation and cost. No trying to get computerized fuel curves and such right. If you have your heart set on it for driveability and starting, go for it. Part numbers are for specific cams, yes. If you're not going to spin the snot out of the motor, get whichever is cheapest. The big valves have the highest HP potential, but the small ones will be plenty good enough. The only thing about the Vortec heads is the intake manifold bolt pattern is different if I recall correctly, so you'll have to pay attention to what intake manifold you get, you can buy a SBC manifold for 55-95, or 96-??, you'll need the 96-?? one. Also, you could make a 383 out of it, but if I had a 400 crank, I'd just try and find a block to go with it and build the 400. If you get a big 4 core radiator you should be able to keep it cool, as long as you don't let it idle with the AC on when it's 100 degrees out. Alot of the trouble with 400s was due to AC use in hot weather, combined with the radiator/tranny cooler design that Chevy used, it puts heat into the radiator from tranny and motor, which won't be an issue for you.

IMAGE
03-01-2008, 05:17 PM
I would go the 383 route with vortecs. Get the edelbrock intake needed to run TBI on the vortecs. You can safely go slightly larger then stock with the cam, and run the TBI setup. A TBI computer and throttle body should only run you a couple hundo at most. Heck you can get a running TBI with computer and accessories for 5-600$.

You will need a fuel pump that puts out 15psi(if I remember correct), or an electric pump and a regulator.

I had a friend running vortecs on a carbed motor with 10.1 compression, only slight detonation under hard throttle, but you gotta know your gas is good.You should be safe up to 9.4 on even the cheapest fuel. Dont go below 8.8-- thats just asking for a dog of a motor.