Big Block in a 4x4

[mrein3]

I MIGHT be able to get my hands on a complete 454 for my truck. My 350 is tired so I have to do something one of these days. My engine rebuilder friend said for what I use my truck for I have two choices: 383 or 454. He said everything else is pretty much a waste of his and my time.

Given those parameters (383 or 454) I know some of you guys wedged a big block in your 4x4. I don't necessarily have to keep it stock but if I went with a 383 I could simply put that engine in in place of my 350 and use all stock components. If I go big block the General never made a 4x4 with a big block until after 1972. What kind of problems will I run into if I go down the big block path?

Do stock (from 2wd) exhaust manifolds work/fit?
Do stock (from 2wd) engine stands work/fit?

I know a lot of you guys have done this swap. What did you do?

[too much stuff]

I put my 402 on the 350 engine mounts, corvette valve covers (which are notched for master cylinder) and 1977 454 truck exhaust manifolds. The hei is TIGHT to the firewall and so is the drivers side valve cover. Been on the road for about 8 years like that!! Bruce (sakohntr) did similar, but moved everything forward about 2 " i believe. Oh yeah, i have no body lift. If you are in the area, stop in and check it out. Eric

[Bluegoose972]

I'm in the process of doing this swap right now. I shifted the engire forward by 2" to gain clearance. You should be able to get away without shifting the engine if you dimple in the firewall around the tight spots (mainly the distributor). I didn't want to do this, therefore I shifted. As for the rest, I'm going to use the existing crossmember engine mount and I have a set of Poly Big Block engine mounts coming from Brothers. They are suppose to be similar to the small block mounts, just more heavy duty to handle the torque. I'm also using hedman headers (keep your fingers crossed that they will work). As long as your getting a complete engine with all the brackets and misc, you should be in good shape.....And there is NO SUBSTITUTE FOR CUBIC INCHES!

My 454 just dyno'd out, with a mild buildup, at 458 hp and 495 ft-lbs of torque.

[Bram]

Yukon Jack has a new 454 in his 4x4. He hasn't fired it up yet, but has it mounted, looks pretty sweet if I do say so myself. He has some pic's, we'll have to get him on here.

[Yukon Jack]

Here is a link to pics of my big block in the frame along with information. http://www.myoldtruck.com/modules.ph...&pid=12&page=2

I'm very close to putting the cab back on the frame. I did a 2" body lift to get my cab better aligned with my headache rack, but it should help with the cab clearance issues. The engine is sitting in the stock small block location though I did move the crossmember physcially forward about 3/8". Moved the motor mount holes in the engine towers back so the engine stayed in the same spot. Before doing that my clearance for the oil pan and one tube of the passenger side header was tight. I did have to grind the frame a little for the passenger side header to fit.

Happy to answer any questions.

[hllblly1972gmc]

I dont know how much help I can be because I changed a lot on my truck. Its a 1972 GMC 4x4 1/2/ ton short bed. I built all the cross members, sirewall, linkages, etc.... I copied this from another post I replied too, maybe it will help some of you. Or some of you will think Im crazy.

I have a 1972 gmc 1/2 ton 4x4 short bed. Still building, but should be done in the next few years I think. I built a 520 CI BBC. For headers I have the Hookers Super Comp, or Pro Comps cant remember. They fit good so far, but may run into some issues around the transfer case. Also these headers kinda suck because they have thin mounting flanges, I will build new flanges for them where they mount to the heads. I did trim the frame a bit. I am using Merlin heads, so the exhaust ports are a little higher than stock heads, about a 1/4 inch or so. I moved my firewall back 2 1/4 inches. I cut out my firewall and fabbed a new one. The firewall sits about 1/4 inch from the plastic heater box inside the cab. I built a new crossmember, and am using big block mounts. I lifted the body 1 1/2 inches, I cut three inch blocks in half because I didnt want too much lift, already have a six inch suspension lift. As far as the question about the clutch linkage, I ground the old bracket off the frame and moved it so it would match the pivot ball. Then made up new rods for the linkage to adjust for length, also due to the firewall change, my clutch linkage off the pedal is also different, it goes through the floor about two inches further to the driverside. I use tall merlin valve covers and have no clearance issues with the brake booster or heater box, this is a non a/c cab.

I know this reply is long, but theres been a lot of work here.

Im the Be-Cool radiator. My engine is very large displacement, If anyone wants info on it just let me know. Its naturally aspirated, should dyno out at about 620 to 650 horsepower, when I get the truck together I will dyno it at my work, its nice to have a dyno. Also am going to be running a 250 hp nitrous kit, not added into the hp numbers above. Be-Cool makes a radiator for our trucks that will cool up to 900 hp, I think it was about 500 dollars, give or take a little, but not much.








Maybe this will help someone. I am going to alot of work but I want it to be right. If anyone has any questions of anything I did, or maybe something I did wrong

This is the same reply as I did to a few other threads.