Hello. I've been gaining valuable information from this site for several months. It has been extremely useful. I am swapping a 465/205 in place of my 400/350 in the truck now. I was planning on getting a "pioneer" flywheel from auto zone to replace the flexplate. I am getting the luk #04-064 clutch kit which is of the 12" variety. The bell housing i'm using is from the 465/205 from a 78 1/2 ton. If i'm correct, this should be a bolt in affair? The only questions I still have is if the flywheel i'm getting is going to work with the 12" clutch for the 454 motor? Are the pilot bushing and bearings going to work ok? Is there anything else obvious I should think about before attempting this swap? Anybody done this swap with a 400 motor? Am I a jackass for doing this? Thanks everyone!

Just make sure that you use the 400 flywheel as it is externally balanced. The 454 is also externally balanced BUT it has more weight to it and may cause problems. OR you can have the 454 flywheel balanced for the 400 as I have done in the past.

Just make sure that you use the 400 flywheel as it is externally balanced. The 454 is also externally balanced BUT it has more weight to it and may cause problems. OR you can have the 454 flywheel balanced for the 400 as I have done in the past.

Would you recommend any specific brand of flywheel? I've never used any drivetrain components from pioneer, so i'm open to suggestions. I cant find any McCleod flywheels which is what I really wanted.

Gm performance parts lists the flywheel you need # 3986394
specs....
outside dia. 14",
`70-`80 400 ONLY.
uses 11" clutch dia.
168 tooth ring gear

this is recomended to be used with Harmonic balencer #6272225

Is there anything else obvious I should think about before attempting this swap?
Hey you asked ..... pedals bellcrank linkage :laughing:

Hey you asked ..... pedals bellcrank linkage :laughing:

I got the whole pedal assembly from the truck. I'm thinking of converting to hydraulic- after two failed trips to the yard to remove that piece of shit linkage. Is there anybody that can tell me if the pioneer flywheel will work with a 12" clutch? I keep getting differing opinions and would really like to know for sure before I start ordering parts. Some companies say that the 400 flywheel is only for 28? tooth not 10. Some say a 12" will work no problem, others say a 12" will not even fit on the flywheel for a 400. Worst case scenario, i'll order the flywheel for the 400 from auto zone, measure the surface area and see if the big clutch will work or not. I think this is the worst part of the swap... Any help or ideas would be appreciated.

Gm performance parts lists the flywheel you need # 3986394
specs....
outside dia. 14",
`70-`80 400 ONLY.
uses 11" clutch dia.
168 tooth ring gear

this is recomended to be used with Harmonic balencer #6272225

good info, thanks. Would this flywheel work with the 12" clutch since it has a 14" od?

I believe 11 inch it max but order both and return the one that doesn't fit. also All flywheels for the small block will be 14" except for special aplication smaller stuff like some camaro. If it were bigger it wouldn't fit

I'm confused with some of what you're asking.. Are you trying to use a 454 flywheel on a 400 small block? Or no? You're replacing what tranny and tcase with the sm465 and np205? If you eff with the flywheel/flexplate on a 400 small block you're going to have to do some balancing on it to keep your motor in harmony.

I think what you will find is the bolt holes for the pressure plate limit how big you can go on disc dia. the Gm Performance book only lists the one.

I'm confused with some of what you're asking.. Are you trying to use a 454 flywheel on a 400 small block? Or no? You're replacing what tranny and tcase with the sm465 and np205? If you eff with the flywheel/flexplate on a 400 small block you're going to have to do some balancing on it to keep your motor in harmony.

Like I said in my original post... i'm swapping a 400/350 turbo for a 465/205. I need to replace my flexplate with a flywheel for the 465. I thought that all gm small blocks were 14" flywheels but I wasn't sure. I know that the 400 is externally balanced (a few years back I replaced flexplate with a 350 flexplate and shook till I realized it was a 400) but I wasn't and still am not positive if it will accept a 12" 10 spline clutch for say a 454? Hasn't anybody put a big clutch into a 400/465/205 combo? Thanks for all the suggestions and information guys. I guess like one guy said earlier, i'll just order both the 11 and 12" clutches and return the one that doesn't work. Damn prepay at AZ.

stick with the 11" clutch. there are many choices, and the 12" won't gain you anything unless you are building a 500hp drag racing engine.

dont waste your money on an autozone clutch, ive seen many fail prematurely. go to you 'neighborhood' part store, or a napa or somthing similare and get a b&w or somthing similar. and buy one for a heavy duty, or dump truck application, it have the big 3 fingers instead of the diapham type. ive been running these clutches for years and never had one fail, and i abuse things. if u really want a no fail solution, get a ceramic clutch, theyre expensive, but take alot of abuse, as for the 12'' clutch, i would imagine it would fit inside the bell, since the 454 and sb bells are the same, as for the flywheels, ive seen them have 2 sets of holes for the clutch to bolt to, i would guess that the other set is for the larger clutch, but i really dont know for sure.