Been a bit since I had time to push forward on my project. I have a 1951 Chev wheat truck I'm updating to be safe and reliable for anyone to drive 55mph (that is if they know how to drive a stick ). I sourced a 1991 P30 chassis RV for my parts donor. It has a TBI 454, 4L80E, 14bolt setup. The 14 bolt is different than any I've ever seen, but that's a topic for a different thread. I figure the 454 mated to the SM420 with the newer 14 with 4.56 gears will net some drive-ability over the old 235/SM420/6.13s that the truck has now. The ratios in the 4L80E just ain't in my interest. Plus it's an auto. I like my old trucks standard. Ironically I don't have much experience mechanically with standard transmissions. All my 80s chevy trucks I broke and wrenched on as a kid had turbo 350s or 400s. So what's involved in putting a 454 to a SM420? I've gathered that I'll need a different bellhousing. I've read that they're pretty common. 63-67 bellhousing I believe. I've read something about a starter issue. What about the clutch, flywheel, pressure plate, throwout bearing, clutch fork, and pilot bearing?
454's are externally balanced. So make sure you get a flywheel for a 454.
Could you link me to an example? You seem to know what you'd look for. Or direct me to the variables that I should be concerned about. Flywheel size, number of teeth? I hate asking for knowledge on a silver platter, but I've got so much going on I'm humbly begging for easy concise answers.
Does your existing truck have a 420 in it now? You might come across a 465 which would also work. You can also probably get a higher diff. ratio for the 14 bolt, full flotation, I presume. However, one needs to match up front/rear bolt patterns, are you going to use front and rear axles from donor?
Ed
'37 GMC T-18 w/ DD 4-53T, RTO-610, 6231 aux., '95 GMC running gear, full disc brakes, power steering, 22.5 wheels and tires. '47 GMC 1 ton w/ 302, NP-540, 4wd, full width Blazer front axle. '54 GMC 630 w/ 503 gasser, 5 speed, ex fire truck, shortened WB 4', install 8' bed. '55 GMC 370 w/270, 420 4 speed, grain, dump bed truck from ND. Works OK.
Does your existing truck have a 420 in it now? You might come across a 465 which would also work. You can also probably get a higher diff. ratio for the 14 bolt, full flotation, I presume. However, one needs to match up front/rear bolt patterns, are you going to use front and rear axles from donor?
Ed
See if I can throw this out in a concise way.
Parent truck: 1951 wheat truck. 6400 I believe. I have taken the engine and drivetrain out, but these were the contents- 235 I6, SM420 transmission, original banjo rear end with 6.13 gears
Answer to your question- Yes I have a 420 now. I would like to use it for the reasons that I have it, and I'm not interested in the SM465 ratios as I plan to use this truck for real work like hauling grain or dirt. I like that super low 7.05 first gear to pull out of a field onto a road under load.
Donor vehicle: 1991 P30032 chassis RV. As it sits it has- TBI 454, 4L80E, 14bolt with 4.56 gears
Would like to make the parent 1951 truck have the combination of TBI 454, SM420, 14bolt with 4.56 gears.
4.56 gears will move me down the road at a comfortable RPM. The 454 will have the a$$ to push it. The SM420 has a wide set of ratios that the power of the 454 can cover. The 14bolt rear end has disc brakes. I'll rob all the modern brake components i.e. booster/master cylinder. I'm still figuring how to make the front disc, but that's a different thread.
). I sourced a 1991 P30 chassis RV for my parts donor. It has a TBI 454, 4L80E, 14bolt setup. The 14 bolt is different than any I've ever seen, but that's a topic for a different thread. I figure the 454 mated to the SM420 with the newer 14 with 4.56 gears will net some drive-ability over the old 235/SM420/6.13s that the truck has now. The ratios in the 4L80E just ain't in my interest. Plus it's an auto. I like my old trucks standard. Ironically I don't have much experience mechanically with standard transmissions. All my 80s chevy trucks I broke and wrenched on as a kid had turbo 350s or 400s. So what's involved in putting a 454 to a SM420? I've gathered that I'll need a different bellhousing. I've read that they're pretty common. 63-67 bellhousing I believe. I've read something about a starter issue. What about the clutch, flywheel, pressure plate, throwout bearing, clutch fork, and pilot bearing?