I have a 1965 GMC 1500 Series pick-up truck. It has the standard tranny and the 305 V6. Even though the engine is good and only has around 40,000 miles on the rebuild I would like to put a 1965 327 Chevy V8 into the truck. The 327 is minus the Bell Housing and pressure plate. I was wondering is the V8 will bolt right of the the 305's Bell Housing and if I can utilize the Pressure plate, throw-out Bearing and existing yolk. I have had a lot of trouble finding the answer. It seems too specific to find the answer I need. Thanks for your help and time. I would rather not start something just to find out there is more involved and I was not prepared. Mark
You need the Chevy bellhousing, as well as the frame mount brackets and motor mounts. I don't know if the clutch is the same, my guess is you need the Chevy clutch too. You could look on rockauto.com and see if they show the same part number for both trucks.
That is an unusual swap. Describe the transmission, is it a top loader 4 speed with granny gear? Or is it just your typical 3 speed on tree? My thinking is that the transmission will bolt to a truck Chevy V8 bell housing, but don't know if the input shaft would match up with the crank. If the bell housing you have is like the typical chevy V8 bell housing (5 bolts with center one at top of the "roof") then in all likelyhood you will be able to put the SBC in.
The input shaft is the same. The bellhousing is very different. I did one of these a year or two ago.
How different are the bell housings and are there any engines besides the GMC variety that will bolt up?
You guys haven't seen "unusual" until you do a factory A/T swap into a stick 305/351 V6. There were two totally different flex plates for P/G or TH400, and both used a big heavy stick-looking flywheel, besides the goofy looking triangle shaped flexplate. ...and if you get lucky enough to ever find a flex plate for one, 90% chance it's cracked at least at one ear. ...because those motors vibrated too much.
The GMC V-6 engine doesn't have a flange on the back, it's more like a 235 in that regard. So the bellhousing has big flange on the front of it. The mounts and transmission end of the bellhousing are the same as a chevy.
Flexplate sounds much like a Buick Dynaflow flexplate. Squirrel: So the bellhousing kinda bolts to the block in a narrow pattern like a 235? GM sure liked being different for every brand they manufactured.
The transmission is a 4 speed manual with the Granny gear. The truck is a daily driver and I really didn't want it to become a huge project. I can always sell the 327. I got that for free from a friend who pulled it out of his old 65 Chevy truck. I wanted to get a V8 put into the truck for a bit more power and the ability to do more than 40 on the hills. Is there another GM V8 that will drop right in without any mods? Thanks for any help and I cannot believe how hard it is to find what I need. Thanks again all.
Nothing will bolt in in place of the V6, the Chevy V8 is probably the easiest swap there is, since you just have to get the parts that fit the Chevy engine to the truck, and you're done.
It's not the engine being the problem. You will need a different bell no matter what other V8 you try to swap. That chevy bell should be so easy to find, to fit the 327 and the 4 spd truck trans. Got any friends of friends, that are old time chevy nuts? they could do that swap easy, and tell you where to find local parts for it.
get all the parts out of the donar truck before it goes away and that will make your life much easier. the guys on 67-72 chevy truck forum can help also. post some pic's here of your engine swap.
The transmission itself should be the same (SM420) between the GMC and Chevy. This was a popular unit found mostly in the C20, C30 series trucks. I don't think anything is a direct swap for the GMC V6. I've always seen the SBC dropped in. Bob
I believe the back of the V6 has an SAE mounting for the bell. They are a round flange with equally spaced bolt holes. I think there are 3 different sizes depending on the output of the engine. This is probably the smallest of the 3. This makes switching engines on trucks and industrial equipment easy as engines of the same relative power are compatable with each other by different manufacturers, but complicates the automotive end of things. Medium and large truck Diesels also use the SAE standard flanges.
The GMC engines that were installed in big trucks had an SAE adapter bolted to the back of the GMC block, then the SAE bellhousing bolts to the adapter. The back of the block is way smaller than the SAE bolt pattern.
Society of Automotive engineers. They set a lot of standards....one of them is a series of standard bellhousing bolt patterns.
If you have the old motor mounts and they are in solid condition, I would like you to call me, please? Mike 843-761-7333 (H#) C# 843-834-0827
Does your truck have the hydralic cylinder that works the clutch? If so I believe you'll have to have the bellhousing with the boss to bolt the slave cylinder to. If not I have a bellhousing that will work for you.
@ lowcountryman44 the motor mounts for the V6 305 are in perfect condition. I have a 327 with the clutch parts and bell housing which should mount to the current transmission. I am currently speaking with the Auto shop teacher at the high school my boys attend and he may be willing to just do the swap for me and using the V6 as a rebuild project and sell it to fund the shop program. We shall see and thanks everyone for all of the advice. The shop teacher is one of 3 Auto Shops left in our school District and here in Nevada the District is the entire County and he is pushing to make his the best shop to try to keep the program alive. I am willing to support that if he is willing to take it on. After all we need more Shade Tree Wrenchers like us in the world.
I have a 327 V8 that I didn't know was covered in my dads garage and I picked up the clutch parts and bell housing from a guy here in Reno. It is the 4 speed with Granny and I am told it will bolt up but the Bell housing was the key to doing so. Thanks for your assistance.
A 40,000 mile 305 doesn't need a rebuild, it's just broken in ?? ... but you could certainly sell that motor to someone to fund any parts you need to buy.
It was only a partial rebuild and it has 2 dead cylinders now so an engine replacement as long as I have one available to me I may as well do it.
That explains the 40mph, No compression in the two? or needs a tune up? I like those motors, growing up my dad had a 62 GMC 3/4 ton Custom cab. 305 V6, 4 speed hydromatic, big back window, power steering, power brakes, positraction, deluxe heater, Cloth seat, keyed door locks both sides etc. I've never seen another one optioned like that, I sure would like to have it today. It pulled good, 5 in our family, 11 foot camper and a motorcycle on the front, and it would pull the pass at 60.
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