1st Gen. Ram - All Topics Discussion for all Dodge Rams prior to 1994. This includes engine, drivetrain and non-drivetrain discussions. Anything prior to 1994 should go in here.

Bolt in replacement for first gen cummins

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Old Jul 26, 2024 | 12:22 PM
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Bolt in replacement for first gen cummins

Whats the bolt in upgrade for the first gens? Engine is fully rebuilt to about 300 hp, transmission is rebuilt, new torque converter, etc so dont want the stock flexplate as the weak link here. Ive researched quite a bit the last several days and just not finding what im looking for. Is the 2nd gen plate a good upgrade? And im not sure whether the aftermarket billet ones from BD diesel and ATS are bolt in or require spacers. Also not looking to spend more money than i have to. Want a strong plate thats not gonna shatter when i need it most but also not building a 700hp racing truck. Just a 300hp daily driver with some towing and the possibility of turning it up more if i feel i have to.
Thanks in advance
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Old Jul 26, 2024 | 12:25 PM
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1989 12 valve with 727
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Old Jul 26, 2024 | 12:29 PM
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I do not build auto rigs often, so when I built my '76 Ramcharger with a P-pumped 12V and a 47RH. I got a SFI [?] rated flex plate from Crazy Carls.
I did note some mild interference with the inner bump out in the flex plate and the adapter plate when I was hand turning over the motor. A bit of work with the grinder made it work out fine.

I was worried about either the 1st or the 2nd gen flexplates being strong enough.
I am figuring I will have 500 HP at the flex plate with my set up.
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Old Jul 26, 2024 | 03:41 PM
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Originally Posted by oliver foster
I do not build auto rigs often, so when I built my '76 Ramcharger with a P-pumped 12V and a 47RH. I got a SFI [?] rated flex plate from Crazy Carls.
I did note some mild interference with the inner bump out in the flex plate and the adapter plate when I was hand turning over the motor. A bit of work with the grinder made it work out fine.

I was worried about either the 1st or the 2nd gen flexplates being strong enough.
I am figuring I will have 500 HP at the flex plate with my set up.
Right, but thats a second gen setup though... Just called bd wether or not their 94-07 billet flex plate will work on my 89. Had a girl on the phone who said it wouldnt fit my 89 as its completely different, and balanced different since its a whole different motor....
i dont really believe that lol but hey who am i to question it. I think if there would be a difference its that its a little thicker and would need a spacer
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Old Jul 26, 2024 | 06:07 PM
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From: BFE, Pennsyltucky
Isn't the 47RH a better version of the 518, like better internal squish box parts? I think the 47rh and diesel 727 share the same bellhouse adapter? I could be wrong, I only have one auto CTD. I'm certain that the short block of all mechanical 5.9s are the same, but the 24V stuff gets a little different.
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Old Jul 26, 2024 | 06:11 PM
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Originally Posted by BHD
Isn't the 47RH a better version of the 518, like better internal squish box parts? I think the 47rh and diesel 727 share the same bellhouse adapter? I could be wrong, I only have one auto CTD. I'm certain that the short block of all mechanical 5.9s are the same, but the 24V stuff gets a little different.
thats exactly what im not sure of either. I do find it strange that all the fancy flexplates are listed for 94-07
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Old Jul 26, 2024 | 06:45 PM
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Yeah, just order it up for your '89. I was going to use that flex plate on any12V motor I choose in the shop.
As BHD said it is the same block '89-'98.0..
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Old Jul 26, 2024 | 11:42 PM
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The best flex plate for 47RH would be the shot peened from the 08 and up. Mopar number 68005249AA

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Old Jul 31, 2024 | 11:09 AM
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Has anybody tried this one on a first gen? Can get one cheap close by new never used
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Old Jul 31, 2024 | 01:41 PM
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From: vermont
That looks like the one I used. Check that the locating tabs on the back do not rub on the adapter plate. I had to grind mine down a little bit.
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Old Sep 3, 2024 | 02:14 PM
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Originally Posted by Barend
thats exactly what im not sure of either. I do find it strange that all the fancy flexplates are listed for 94-07
Its because the 47rh/re came with a lockup TC and they are thicker, the input end of the transmission case is different to accommodate that and possibly a different size flexplate (read also 2nd gen starter) I put a goerend TC in and reused my flex plate. I had to replace my a518/46rh transmission case and they're specific to our diesel 89-93 application.

Dave? at goerend is very helpful for old dodge diesel applications and he had better ones if you haven't sourced one yet. He also talked me out of a low stall even though I thought that's what I wanted
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Old Sep 3, 2024 | 07:34 PM
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I got one about 10 years ago and Dave tried to talk me out of low stall but I held my ground. Engine will sometimes stall when cold and A/C is on in gear when you let off throttle quick. Idle about 600RPM. My service truck weighs 8500 lbs and I pull 10K trailers. I like it with low stall.
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Old Nov 30, 2024 | 04:05 PM
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Still looking for a flexplate. I hear alot of people using the second gen plate. Theres no listings for second gen plates right now but there is for the 3rd gen with the 48re transmission. Do they work also? Thanks
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Old Nov 30, 2024 | 04:20 PM
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From: BC
The flywheels swap pre/post 93/94, so I'm not sure why the flexplate wouldn't.

The reason for the (aftermarket) HD flexplate is the lockup found on the 94+. That's where a lot of stress comes in. Add an exhaust brake, and more stress again.
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Old Dec 1, 2024 | 07:38 AM
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Let me dig around I was looking for one for my 93. Commented on a Decent Garage video and he told me where he got his.
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