I am at the beginning of my 3600 restoration project that includes plans to convert to a SBC and I am looking for input/feedback regarding the approach others have taken. Overall project goal is to have a great looking truck that I can drive and show that will be comfortable to drive on country roads at 55/60 mph. May do some limited hauling/towing but not really a priority.
First some basic thoughts (nothing set in stone):
I plan to keep the 3/4 ton 8 bolt wheel pattern and original axles/suspension, I have read a bit about rear axle ratio changes to reduce the original 4.56 ratio to 4.10 and am anticipating going to a NV3500 or 4500 transmission to get overdrive, I am anticipating a disk brake conversion for the front and possibly the rear, I anticipate converting the steering to power assist, and I have a 350 SBC that spun a rod bearing so needs a complete rebuild. Not sure what wheel/tire size to shoot for but clearly that interacts with the rear axle ratio discussion.
I am considering building the SBC as a 383 given that I need to replace all the rotating parts anyway but realize either a 350 or the 383 will have a lot more power than really needed. The engine was from a TBI version, 1991 Chevy 2500 but I anticipate utilizing a carburetor set-up rather than fuel injection to keep it simple. I do not anticipate using the 1991 cylinder heads due to poor performance so probably Vortec heads with the correct intake manifold to utilize a carburetor. Cam selection to be matched to the displacement/heads/compression ratio etc. to provide a reasonable idle and low end torque appropriate for a truck engine.
I have seen several options for SBC engine mounting (bolt in and weld in) but I am a little unclear about the need to modify the firewall for bell housing clearance and/or rear engine mount changes required. The original in-line 6 has a 4 speed SM 420 transmission which just hung off the back of the bell housing but I needed to remove the transmission separate from the engine because the transmission would not fit between the cab and the rear cross brace. Ideally I would not modify the firewall for clearance but as I need to make cab floor repairs as part of the project I would prefer to know if modifications are needed before I get too far with the cab floor repairs. Also curious about drive shafts as the original was a torque tube from the transmission to the intermediate bearing with conventional from the intermediate bearing to the rear axle. I have read somewhere that a single shaft from the transmission to the rea axle may be too long.
I have read about exhaust manifold to steering gear clearance issues with various solutions including: no problem with original gear, spacing out the original gear with a modified drag link, newer gear (manual or power) mounted outside the frame and forward of the axle, and probably a few others but curious of pros and cons for various options given that I prefer to go to power steering anyway.
I anticipate utilizing a new radiator with either an engine fan/shroud or an electric fan/shroud set up.
I have also read about fuel tank options for under the bed near the rear with the fill either located in the bed floor or possibly out the side. My first thought is to go out the side but would appreciate input from others regarding what tank and fill set-up was chosen and any pros/cons.
Thanks for reading.
