HEMI Tech- Transmission adapters, flywheels, starters

I'll gather up some photos and get started on a post with tech and have it up for the weekend. Thanks for all of the kind words.

 

is this going to be an extended block tech right? That would be awesome!

 

First off let me say I'm not here to shill or spam. I'm only posting this because I was asked to. I do appreciate the fact someone asked my opinion and hope this post is helpful to you and the rest of the HAMB.

1st question is what engine do I have and how do I identify it? Thankfully Chrysler used a common block and crank shaft pattern on the Dodge, Desoto and Chrysler Polys and Hemis EXCEPT for the 1951 to 1953 331c.i. Chrysler, also called an extended block. The extended block has a round pattern that is similar to an S.A.E. pattern found on industrial engines and uses a cast starter housing that bolts vertically to the engine. One word of advise; don't lose the starter housing as it can be tough to find. The rest of the Hemis use a bolt pattern is common to the Chrysler LA Small Block and the new 5.7L Hemi BUT the dowel pins are in the different locations and the crankshaft stickout distance is different. And while you can bolt a LA bellhousing up to the early Hemi, there's a lot of grief involved in getting it right and even more if you don't. Also the 426 Hemi flywheel has the correct bolt pattern but does not register on the flywheel correctly and can't be used (Sorry Dale). The Donovan 392 aluminum block uses the same bolt pattern/crank but with additional holes.

The crankshafts all share a common 8 bolt pattern and all used the outside diameter of the flange to register the flywheel. One bolt hole is offset. They all used 7/16" bolts to attach the flywheel and stock they are not threaded. The holes are drilled to a few thousands over the tap drill size for 1/2-20 NF. If your going to install a manual trans its worth the time to tap the holes. Use a good sharp 3 or 4 flute tap and good tapping fluid and keep it square to the flange. If you get it wrong or don't like the way the threads come out you can always run nuts behind the flange as security. Just don't break the tap off. The pilot bearing bore diameter in the crank can be 3/4", 15/16" or can be bored for a ball bearing or may have no bore at all. Torque spec on the crankshaft bolts is 55-60 ft-lbs for the stock 7/16-20 fasteners. Engine is neutral balance.

2nd question is why even bother with an adapter? The Hemi is designed to use a transmission adapter. The stock automatics used a transmission adapter, sometimes called a starter plate. The crankshaft stick out is longer to compensate for the adapter plate. The stock transmission were not bad for their day but today we are so used modern transmissions that I doubt anyone would really be satisfied with the performance of the stock units. And while they are not complex transmissions, finding parts can be hard. The Fluid Drive was first introduced in 1938 and was really a fluid coupling with a dry clutch and a 3 or 4 speed transmission bolted to the back of it. There were various schemes used to shift and the driver used the dry clutch to shift between forward and reverse. Sounds like a good idea but the fluid coupling, flywheel, disk, and pressure plate weigh a lot and didn't offer any torque multiplication. In 51 came the Fluid Torque with a true torque converter then the 2 speed Powerflite in 54 and finally the 3 speed cast iron Torqueflite in 56. The cast iron Torqueflite shared some of the basic design with the later A-904 introduced in 1960 but weighs in at over 200lbs.

There are plenty of adapters out there and plenty of people making them. They range from guys pushing around a shopping cart at the swap meet to big warehouse distributors and the rest of us in between. Chances are if they've be around for a while then their product works. I haven't seen everything that’s out there but I've seen a lot of them. I can really only be specific about my product but I believe most of this applied to the majority of adapters on the market now for the early Hemis. The 331 extended block is a entirely different animal and below is a section just for that.

So which transmission is best? With the choice of adapters it's pretty wide open. Right now for the conventional block you can bolt up Chrysler small block auto and manual, the Chevy auto or manual, the Ford small block manual and the Ford flathead trans (32-48). I hope to have the Ford small block auto done soon. There are no adapters now available for the BB Mopar or Ford(s) that I'm aware of.

Mopar adapters place the starter in the stock small block position and may require the block be clearance for the starter to fit. Mopar auto adapters need to run a the neutral balance torque converter from the 318 and make sure the flexplate and convert bolts are on the same bolt circle before installing.

Chevy Auto adapters are available for the Powerglide, TH200,350,400, etc. and the 700r4. the starter can be put on either side but starter placement on the passenger side (USA) most of the time will require an oil filter adapter or remote. Adapters are available for the BOP auto as well.

Ford/Chevy/BOP manual adapters use the stock transmission bellhousing and use a special thicker flywheel to bring the flywheel out to the correct height and generally place the starter on the side that was stock for the bellhousing (pass side on Chevy and Ford, drivers side for Buick, Olds, Pontiac) but specials can be made. On our Chevy manual adapter the 10.5" Chevy bellhousing works best and any of the Ford SB bells fit on the Ford SB adapter. Best practice is to use the bellhousing/throw out bearing/arm that was with the transmission if possible.

All of the early Ford (1932-1948) adapters (Wilcap Offenhauser, Cragar and others) used the stock starter and flywheel. These are the only adapters that use the stock flywheel/starter combination due to the fact that the stock ring gear dimension is bigger in diameter than the inside diameter of the modern bellhousings. The stock flywheel /starter can be used to with the early Ford adapter and a flathead to Chevy or Ford adapter to run those transmissions but the second adapter may need to be cut down for correct throw out bearing operation. The flathead Dodge I6 flywheel interchanges with the Hemi. The ring gear changed in 56 from a 146 to 172 teeth when the 12V starter was introduced. All of the early Ford adapters were 2 piece designs that used a plate that bolted to the block and then the bellhousing bolted to it. The Wilcap adapter uses a stock Chrysler adapter or starter plate (3/4" version).

331 Extended block adapters are fairly simple plates and all use the stock starter/flywheel (other than our adapter for the A-727 which uses a supplied flexplate). Unlike the conventional blocks, the extended block manual adapters bolt directly to the transmission and don't use a bellhousing. The GM adapters are for the "Muncie" bolt pattern and so will accept the Saginaw, Muncie, BW T5, etc. The Ford adapters are available for the Top Loader 65-78 and T5 and can be made for the 55-64 transmission as well. Also available is the Cad-LaSalle adapter and the adapter to run the A-727 auto with the bellhousing cut off. I have built one for the GM 4l60E but this is a computerized 4 speed overdrive and requires a separate controller for the trans. The Mopar A833 manual can be done but if your crank has the 3/4" pilot hole then it's a real problem due to the fact that the input pilot is also 3/4". The early Ford 32-48 adapter is no longer in production but they show up on ebay and at swap meets. Because of the length of the input shaft, the transmission actually sits inside of the bellhousing extension on the 331.

The big issue with all of the extended block 331 adapters is the throw out bearing. The throw out bearing arm can be bent to work but still there may be some cutting on the block or starter housing. The best bet is to go with a hydraulic bearing like the McLeod or Howe. Another idea is to mount a push slave cylinder on the adapter plate operate the fork that way. If you do use a mechanical arm use the long forged GM arm.

Troys Machine in Boise is still cutting the back of the block down on the 331 so that's always an option. They weld a standard Hemi flange to the back after machining off the extension.

As I said before, you can get the Mopar and Chevy adapters from a number of sources. Most of the adapters I've seen on the market are fine and will work without any problems but use your common sense when shopping; The dowel pins have to be used to align the engine to the transmission. Bolt holes are not held to a tight enough tolerance. The adapter plate has to be flat AND parallel. There is a difference between flat an parallel; flat means the surface is all on the same plane with no dish or bow or bend to it. This can't be measure with a caliper or micrometer. The surface has to be leveled then indicated in. Parallel can be checked with a micrometer but the only critical dimension in the area where mating faces meet. Billet plate doesn't come from supplier flat unless it comes with both surfaces ground or milled. The rotating assembly has to have a positive register on the crankshaft and should register on the crankshaft using the same method as the factory. Using only the crankshaft bolts to register or align a flexplate or flywheel WILL NOT WORK AND IS DANGEROUS!! Flywheel/clutch disk/flexplate explosions are nothing to screw around with. Best case is you'll destroy a lot of expensive parts and the worst case is you, your passenger, or some innocent bystander are DEAD. Scattershields, transmission blankets and flexplate shields weren’t invented because they look cool. Those are all tombstone innovations, stuff that gets made because someone got killed or seriously injured. If your really going to go fast, spend the money and buy some protection.

As far as the machining, CNC is great but only as good as the operator, the program, and the fixturing. Even when all of that’s good, stuff happens and the seller should be willing and able to stand behind the product and get any problem corrected. I am far from perfect but if an issue comes up, I'll do my best to get it taken care of. But the bottom line is you should spend your money with whoever you feel comfortable with.

Read the instructions. Twice. Call the manufacturer if your not sure about something. When installing the adapter or any trans/bellhousing for that matter, make certain the dowel pins are in place and not mushroomed over. Chrysler pins are 1/2" undersize (-.002") but don't use hardened dowels if you need to replace them. Clean the back of the block and tap run a chaser through the holes. If you have a broken bolt in the block, spend the time to get it out. If the threads go away during extraction use a helicoil but don't skip bolts. Check the crank for dings or burrs and file them off if needed. Check the fasteners and make sure they’re not going to bottom out in the hole before they clamp to the plate or bellhousing. Install the adapter plate and then the flexplate/flywheel. Check the crank bolts and nuts for clearance around the rear main seal and block. If your’ putting the pilot bearing into the crank make sure the old pilot bearing is out first. Trial fit as many of the pieces as you can before final assembly. Check the starter to ring gear engagement before instaing the trans/bellhousing. The pilot bearing should be a tight press fit into the crank. Use washers on everything and locktite on the crank bolts. 3/8-16 bolts torque to 31 ft-lbs on grade 5 (3 lines on the head) and 35 on grade 8s (5 lines). 7/16-14 are 50 lbs and 57 ft-lbs. Don't use grade 2 or non-grade bolts. Take your time, do it right the first time and stop if something doesn't look right.

The book Ron Cerridono wrote for Tex Smith Publishing is worth the money if your building a hemi. It covers most of this and a lot more.

If there something I can help with or you have any questions, email me from the button on my website Wilcap.com or call. I don't get over here to the HAMB as much as I should but I check my PM as often os I can. I hope this is of some use to you and the HAMB and thanks for asking for my opinion.

 

BRAVO PAT!! Thanks for the info. Ill definately buy your adapter when the time comes.

 

HOLY CRAP PAT! Now that is a post of information!

 

Great post...Thanks!

 

Awesome, Thanks!

 

Thanks Pat . . . as always, you do a great job. Yep . . . as you mentioned in your post - I have a nice spare SFI rated 426 flywheel laying around. I thought it was going to work, but as you said . . . the ring gear was in the wrong place. Next time I'll listen to you the first time! I'll send you the pictures of my final setup once I get to my assembly stage (it's getting close!). Dale

 

ok, but I still haven't got my question answered...where does the clutch fork go through the extended bellhousing on the early 331 blocks? I just don't see any place for it to mount to on the bellhousing or the lower dust cover...I'm still friggin confused, anyone got pics of their clutch fork setup on an extended bellhousing 331?

 

Great post !!!!! I needed this.

 

Thanks you sir!!
I have a Wilcap adapter on my cabriolet and on the pheaton. The swap was easy as they come with all the correct parts..The best part was service, I had a question and it was answered and they(Pat) help me thru it.. I have to say my choice hands down for any adapter because of customer service and quality parts!!!!
Proof is in this post with Pats reply! Thanks Pat for a great post!!
thanks John

 

BTTT for johnny... I would also like to know this!!!

 

I thought he did answer this question:

I too have a long bell 53 331 and was curious as to the solution. It sounds as if the simple solution is to run the hydraulic relase bearing. I have reservations about these damnedable things but they do work well. If you don't want to use one it sounds like there is some fabrication involved.

 

I saw someone (on a video to remain nameless and name withheld to protect the innocent) actually cut a slot in the lower bell cover for the fork. I would like to see one of these set-up. A hydraulic T/O bearing sounds like the most simple solution if set-up and bled correctly, but have heard what a pain it is to get them set-up. This really is something that should be discussed though. The extended bells are just different enough to make this a good topic of discussion. So we need pics and stuff guys! Let's see 'em!

 

there's no way I'm running a hydraulic setup, not gonna waste my time with that...did all extended block 331's come with the Fluid Drive, or were there manual tranny versions too? There's got to be a better solution than cutting into your bellhousing and trying to make a clutch fork work...there's got to be people out there with the early bellhousing and a manual tranny, right?

 

there's also no way I'm going to waste my time having a small block 727 modified (bellhousing machined off and bolt pattern added) to put behind a car I fully intend on flogging regularly at the track...does the Muncie/Saginaw style adapter need the same style of bellhousing modification to use a clutch fork?

 

I've got an old early hemi to GM 3/4/5 speed adapter that I picked up for my '52 331. I'll dig it out and let you know what the fork provision looks like.

 

thanks man, that'd be a killer help...I'm assuming yours is a wilcap or offy adapter?

 

You guys have another great resource in http://www.hothemiheads.com/
Bob is a super guy and will answer any questions as well. There is a bunch of good info on his site as well. He also has a forumn set up that has a bunch of Hemi guys helping each other out...

 

I think it's either an old Offenhauser, or Speed Gems.

 

stolen directly from the HotHeads website:



(EDIT: Hot heads may not allow linking to thier picture so you may have to click the address, http://www.hothemiheads.com/transmission_adapters/51-53_chr_chevy_manual.html )


This is their 51-53 Long bell to GM trans adapter. As you can see the opening for the clutch fork is there but by the looks of things you may need to notch the engine/starter housing for extra clearance for the release fork to travel. Otherwise it may be necessary to modify or fabricate a new release fork with a dog leg in it to clear properly.

I have used the Quarter Master hydraulic release bearings with good success before. But as I mentioned before I do have reservations, why?

Do you remember me asking for help for a friend of mine with clutch issues a while ago? He has a QM release bearing in his small block Mopar with a Tremec TKO 600. The clutch wore to the point where the diaphragm touched the bearing, no more free play. This was just like riding the clutch and caused the clutch to wear faster.

These bearings use cone shaped shims behind the bearing housing and require you to remove the transmission to add or subtract these shims as needed. On his particular case there was only one shim to start with, and in some instances I have set them up without shims!


I just removed a McLeod bearing from a 514 Ford/Tremec TKO set up. I never used it as it was cheesey and had no means of support for the bearing housing. The housing is on a threaded collar which allows you to spin the housing around to adjust the free play. Sounds like a neat idea and would solve the problem of having to remove the transmission, but I was told by thier tech department that I needed to anchor the pressure and bleed hoses to the bell housing. Now I don't know about you guys but my experience has been there is a considerable ammount of pressure on that bearing and therefore a lot of force to rotate that sucker. Just the thought of using a braided stainless hose as a restraining strap seems rediuclous to me.... unless the tech didn 't know what he was talking about.

I replaced that goofy system with a billet fork and CNC external slave cylinder from Forte's Parts Connection www.fortesparts.com



We just got everything working and I can tell you it works perfectly. I will take some dimentions in a bit and let you guys know the details on space needed.

 

screw it, I'll just find me an M20 or M21 Muncie and get the HHH adapter...unless the A833 adapter from someone else has the cutout for a clutch fork...who carries the A833 manual to extended bellhousing adapter? is Wilcap the only game in town for that particular piece?

 

I checked out my adapter; it looks like the picture ELpolacko supplied.

 

I still haven't seen what the Ex. Bell. early hemi to A833 adapters look like, but in the Wilcap info it says to run a hydraulic throw-out so I'm guessing that there's no provision for a clutch fork...any chance you'd be willing to sell that adapter HEATHEN? or anyone else for that matter?

 

Sorry, as long as I've got the 331 in my garage, I'll hang on to the adapter.

 

alright, just to ease my mind...and because I've forgotten...does the T-10 manual fit the Muncie/Saginaw mounting pattern and have the same mount depth as those other two GM manuals?...and will a T-10 hold up to some 450-500lb/ft of torque when the clutch drops and the front wheels come up? Or would I be better off finding a Super T-10?

 

Yes, one of the advantages of using General Motors transmissions is that, for the most part, they kept things simple. With very few exceptions, ALL '55-up standard transmissions used what has come to be known as the "Chevy" pattern. All Saginaw/Borg Warner/Muncie four speeds will bolt in place of each other, and the only difference I know of is that there were two throwout collar sizes. As soon as I finish this post, I'm off to my garage, so I'll try to take some measurements and post them later this evening. The main reason the Muncie four speed was born in late '63 was that the 409 Chevies and 421 Pontiacs were grinding up the T-10s that were used behind them up to that point, so if you're really planning on stomping on it, I'd think about moving up to a Super T-10 if I could.

 

I'm back. The small front bearing retainer on a late '50s Chevy three speed I've got looks to be 4 inches in diameter, as opposed to 4 11/16 inches on the four speeds in my garage.

 

I'd agree with Heathen --- the regular T-!0s are pretty easy to chew up. The super T-10 is a pretty strong tranny and a correctly setup Muncie is pretty strong as well. As far as strength goes - part of the story will depend on what rear end you're running - and the gear ratio, what tire diameter and type you're running and how hard the thing will hook up. Its hooking the thing up that really puts strain on everything.

I'll be running a blown 392 and a Tremec TKO with 9310 gears in my 34 coupe. The rear is a Frankland 80 Q.C, with SCS spur gears. The car will be pretty light and I won't be running any huge tires in back - so it should smoke the tires pretty easy. I'm hoping the thing will take a fairly good beating and not break too easily . . . will just have to wait and see.