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Parts compatibility between 6.2 and 6.5 TD

Darkrider

Darkrider

Lobo Solitario
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Lloydminster, SK Canada
Ok I already know that i can safely use the top end from a 6.5 TD on the 6.2 but my question is can i use the flexplate from one on the same 6.2? I have a chance to get ahold of a 4L80E transmission for my project and my 6.5 with a spun bearing has the proper flex plate for it. However i plan on using this transmission with my "Red Block" 6.2. Now can i safely use the flexplate from the 6.5 on this engine? The reason im asking is because i know with some engines for example the 318 and 360 Mopar V8s the flexplate isnt interchangable due to the differences in how the engines were balanced. So im not sure if the same case applies here or not.
 
Flexplates are the same for all 6.2 and 6.5 engines.

Seriously the 6.5 is a bored out 6.2 with thinner pistons to keep the weight the same.
Heads, pistons, rings, injector lines, IP's, exhaust manifolds, oil pans, rear main seals, are the only differences. Van and Hummer with the center mount turbo are a little different for heads and intake manifolds. Some differences are not show stoppers for a swap. You can run 6.2 heads with a DS4IP and 6.5 turbo for example.
 
6.2/5 engines are all externally balanced at both the HB and Flexplate / flywheel. Swap parts until you're happy.
 
Good info thanks guys!! So basically i could assemble this engine with the 6.5 heads, S code intake and flex plate as well as the turbo manifolds to make it turbo Diesel. and still use the mechanical IP. And from what i understand the turbo pulls its oil feed from the same point on the block as the mechanical lift pump is mounted on the 6.2 so it would be a simple matter of removing said lift pump and installing the block off plate from a 6.5 with the fittings on it correct?
 
The 'mechanical lift pump' spot is for DRAINBACK on a turbo app. The turbo gets pressurized oil from the engine oiling system at all times. There are a few threads on this here- you might do a search or two.

edit: found this:

turbo oil2.jpgturbo oil.jpg
 
Fair enough. I was told it was something having to do with the turbo that the same spot was also used for the mechanical LP. Chances are im more then likely keeping the engine NA for simplicity like i was originally going to do when considering running it in the Chevelle im picking up. But i will ask this...Will it affect anything to run a Turbo style intake on an NA engine? Just considering it for the ease of being able to add a snorkel to the engine in the application it is going into which is the '69 GMC im building into a trail rig.
 
A turbo intake 'snorkel' would be a little restrictive for N/A IMO.. since the turbo adds positive pressure to force air in..
 
Pics in post 5 is the typical 6.5 OPS and fitting modified for a 90 degree 1/8 NPT to -6 AN fitting for a 36" oil line for a turbo 6.2.. (my current '93 engine)
 
Talking about flexplates.....I've always wanted to know can you even get an aftermarket or updated, thicker flexplate for 6.2 or 6.5 engines? I know I've heard of numerous stories of cracked flexplates causing noise and vibration, so why not fix it with a thicker SFI flexplate. Does anyone sell such a part? Probably very unlikely you could get a billet unit, not that it would be needed though.
 
I don't know of any 'SFI' versions. I think we're stuck with the OEM or plain white box aftermarket 'stuff'

Not sure if GM is even stocking them still.
 
Darkrider said:
Good info thanks guys!! So basically i could assemble this engine with the 6.5 heads, S code intake and flex plate as well as the turbo manifolds to make it turbo Diesel. and still use the mechanical IP. And from what i understand the turbo pulls its oil feed from the same point on the block as the mechanical lift pump is mounted on the 6.2 so it would be a simple matter of removing said lift pump and installing the block off plate from a 6.5 with the fittings on it correct?
Click to expand...

Depending on your budget and need you don't have to swap heads. The 6.5 uses short injectors and the 6.2 uses long style. You can run the 6.2 heads with short injectors, except 1982 fine thread heads, and the turbo manifolds. Clearance is tight requiring manifold gaskets, header wrap, etc. But you can do it. The precups are a major gotcha requiring big ones for turbo applications. The small ones are for MPG and smoke with more fuel esp with a turbo. The 6.2 precups are easy to change out for 6.5 turbo precups.
 
Couple things in red for clarification ...(not picking on you WW)

WarWagon said:
Depending on your budget and need you don't have to swap heads. The 6.5 uses short injectors and the 6.2 uses long style. You can run the 6.2 heads with short injectors, except 1982 fine coarse? thread heads, and the turbo manifolds. Clearance is tight requiring manifold gaskets, header wrap, etc. But you can do it. The precups are a major gotcha requiring big ones for turbo applications. The small ones are for MPG and smoke with more fuel esp with a turbo. this is true The 6.2 precups are easy to change out for 6.5 turbo precups. On my '82 6.2 heads the 'tang' is on the opposite side and interchanging cups will sometimes require cutting/shimming the cup pockets
Click to expand...
 
WarWagon said:
The precups are a major gotcha requiring big ones for turbo applications. The small ones are for MPG and smoke with more fuel esp with a turbo. The 6.2 precups are easy to change out for 6.5 turbo precups.
Click to expand...
:agreed: Indeed, I have a low miles set of diamond precups I am saving for a potential rebuild of a 6.2 core setting in the shop. If it turns out those heads are toast someones going to get a nice set of precups for a bit of folding money ;)d
 
3500GMC said:
Couple things in red for clarification ...(not picking on you WW)
Click to expand...

Can't spell today neither...
1982 heads are the exception to the 'make 6.2 heads work' on a 6.5 turbo setup. So are van heads. Oil pans can be an issue too.
 
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