460 Ford Forum banner

My 521BBF to GM Overdrive conversion

30K views 99 replies 11 participants last post by  thermod 
#1 · (Edited)
Well Ive gotten alot done on the car converting it from a 521BBF with a 3000 stall non lockup C6 which was fully built and very large tranny cooler. I wasn't racing the car as much or at all in the last year as the nearest track closed and was about 45 min away so I would have to rent a car trailer to get the car up. I also started driving the car more to car shows at are like 10-15 miles away and the cruising at 55mph at 3K was killing my MPG and causing alot of uneccessary heat buildup in the trans and motor.

So I decided it was time to swap out the C6 which only had 500 miles on it with a GM overdrive to help improve MPG, heat and the lockup feature sure is nice.

You can choose from the 2004R, 700R4, 4L60E, 4L80E for GM or you can do a AOD, E40D and 470W transmission from ford. My build only covers the GM conversion as thats the route i wanted to do. DUE NOTE that the 2004R, 700R4, AOD are the only mechanical transmission out there that will NOT require some form of ECM or electronic transmission control. Thus this makes it alittle cheaper and easier to swap into an older vehicle depending on the route you go. I decided to go with the 2004R as it has a better gear spread than a 700R4 and a AOD would cost alot more to build up than the 2004R to retain the lockup (if you can on the AOD) and handle gobbs of power. The 2004R is a weak trans stock behind most models except the buick turbo 3.8L but all can be built to handle 500-1000hp reliably.

2004R gear spread.
2.74:1
1.57:1
1:1
.67:1 overdrive with lockup converter :)

Transmission upgrades I performed with a good core trans from a 87 monte carlo with a 305. Cost me 125$ from a somewhat local guy. I purchased a $1400 rebuild kit from CK performance (hes the top guy for these transmissions) that included upgraded frictions/steels, Billet servo, hardened sun shell and stator, wide band, Valve body recalibration and shift kit, his 300 page manual or "bible of 2004Rs" and of course all his BILLET 3040 internal parts. The parts include billet input shaft, forward drum, and overdrive planitary. Built to these specs the trans will handle 800HP/tq no problem and will retain the lockup feature (good luck with that on an AOD). These trans can be built using a cheaper kit (basically just remove the billet input shaft and OD carrier) and that will allow it to handle 575hp/tq all day and thats about 800-900$. Adding the billet parts later will run you about $700+ so its cheaper to get it all at once and get a discount. I purchased a Hughes performance cast aluminum deep pan which is required over 500hp due to case rigid which the cast pan helps alot with, that cost me $179, and a poly trans mount for $20, plus a new mechanical billet speedo (thrashed the old one getting it out) plus a electronic speedo converter both items, $25 and $45 for the converter. I also got a cheap converter lockup kit from ebay for $20 which I wire up with a single 12V line to the trans to lockup the converter, super simple and easy.

Converter time, i decided on a cheaper 10" 2600 stall with lockup good for about 600hp and a small shot of NOS. The converter has to be extended 1/4" to work with the TCI kit I purchased, this includes the mounting pads and the converter pilot. Total cost for the converter was $375. If I decide to upgrade to a billet 1000hp converter it will cost me an extra $350, but not going there yet lol.

TCI adapter kit for GM trans is part # 529700 and costs $489 i believe. comes with adapter SFI flexplate, 1/4" mid plate adapter and neccessary hardware and crank pilot sleeve. This is where I had most of my problems which I will note.

I used a Lokar 2004R universal braided TV cable setup which goes with the other Lokar throttle brackets and such.

I will post a total cost so far but Im hoping to come in at under 3K or close to it. I still need to get a new driveshaft so that is not included yet. I'm going to post pics and stuff after I get back from work.
 
See less See more
#72 ·
Figured I would update this!

Ordered my driveshaft, should have it right after the holidays. Got it for like $30 off as they were having a sale. So I get to keep the one I have for the C6 just in case I need to go back! Also not going to modify the custom C6 trans crossmember as I would have to start all over again so I have that too which means swapping back will be pretty straight forward.

New driveshaft has a total length of 50.5". Going with the same style 3" Denny's driveshaft Nitrous ready with 1350 u joints. Doesnt have a total HP limit as they are basically unbreakable and if it does I get a whole new one for free!

I got a stock used trans crossmember for my car and I will modify it once I get the driveshaft in to make sure its centered in my driveshaft loop. Cost was $30 and factored into my total already.

Also picked up some more tractor fluid to throw into it so i have about 16qts tractor fluid and 2-3 qts of dextrin IV (6).

So add $410 after shipping for the driveshaft and 25$ on the rest of the fluid. I believe puts me at about $3125 total.
 
#73 ·
Im also pricing out the EFI which is going to come to about $2800 if I decide to go with -8 over FAST's -6 setup (kit comes with -6 fittings) which seems awfully small for a single feed line. If I stay -6 the EFI will cost about $2650.

This is after talking with patrick at prosystems and basically told me there is no way to add a choke to this carb. Its no fun starting this thing at 3K and holding it there for a min to warm up in the summer. Hopefully the EFI will eliminate that completely, improve my throttle response and MPG in the city and highway.
 
#75 ·
Well the gear drop alone from a 1:1 with non lockup to a .67:1 is a 33% increase alone. Then the lockup adds even more. I have no idea what mpg it was getting before but I know it was low lol... Going through 5-7 gallons on a 20mile round trip about.
 
#76 ·
plate

Just read through your whole thread and it looks like you had your share of ups and downs for sure.

My engine came with the tci engine plate and it is 1/4" but I didn't have a flex problem at starter because of where my mounts are. It is stiff as a wedding night pr*ck!!! I did run into a problem with my torque converter being bad so I ordered a billet, double balloon plate converter from Competition Transmissions (running blower and nos) and they asked me the thickness of my plate and welded the converter tabs on so they were spaced properly and no washers were needed. I'm running a P/G with a TH350 style converter. While doing it I did find where original owner and project starter used a stock ford flex plate drilled for a turbo 350 converter pattern and the holes were RIGHT ON THE BEND IN THE PLATE.... the one that is for strength. That freaked me out. So I got a new J.W. plate with all 3 bolt patterns in it. I couldn't believe they did that with a 466 running a blower. The tranny it's self looked like something from the junkyard with a pro-tree brake put in it and it never seemed to get my power from the crank to the 33" M/T's... even with an accidental 25 PLUS lbs of blower boost on my last 2 passes. So next weekend I'm running to NY to Comp Trans and picking up my new P/G and dropping off my injection system to be converted to alcohol.

I had to laugh about the MPG thing. After I installed my Enderle injection I was getting GPM!!!! Literally! On racing gas, to make a 1/4 mile run, including warm up, tire burn out, pass and back to my trailer (1/2 mile round trip), I was burning 2 gals of fuel at 8.50 a gallon. That is 4 GPM.... NOT MPG! LOL

And now I am going to alcohol which burns colder, has higher octane BUT uses 3 times MORE than gas. So I will be lucky to make the 1/2 mile loop on 4-5 gallons. So I am told. Another good point is even at 3:1, alky is still cheaper than racing fuel.

Maybe I should look into an OD trans :)

Good thread though and I can see it helped a lot of guys out. I just got a kick on the fuel mileage part :D

Good luck to ya and have a good one!!!!!!

Auggie (ag460torino)
 
#79 ·
Just read through your whole thread and it looks like you had your share of ups and downs for sure.

My engine came with the tci engine plate and it is 1/4" but I didn't have a flex problem at starter because of where my mounts are. It is stiff as a wedding night pr*ck!!! I did run into a problem with my torque converter being bad so I ordered a billet, double balloon plate converter from Competition Transmissions (running blower and nos) and they asked me the thickness of my plate and welded the converter tabs on so they were spaced properly and no washers were needed. I'm running a P/G with a TH350 style converter. While doing it I did find where original owner and project starter used a stock ford flex plate drilled for a turbo 350 converter pattern and the holes were RIGHT ON THE BEND IN THE PLATE.... the one that is for strength. That freaked me out. So I got a new J.W. plate with all 3 bolt patterns in it. I couldn't believe they did that with a 466 running a blower. The tranny it's self looked like something from the junkyard with a pro-tree brake put in it and it never seemed to get my power from the crank to the 33" M/T's... even with an accidental 25 PLUS lbs of blower boost on my last 2 passes. So next weekend I'm running to NY to Comp Trans and picking up my new P/G and dropping off my injection system to be converted to alcohol.

I had to laugh about the MPG thing. After I installed my Enderle injection I was getting GPM!!!! Literally! On racing gas, to make a 1/4 mile run, including warm up, tire burn out, pass and back to my trailer (1/2 mile round trip), I was burning 2 gals of fuel at 8.50 a gallon. That is 4 GPM.... NOT MPG! LOL

And now I am going to alcohol which burns colder, has higher octane BUT uses 3 times MORE than gas. So I will be lucky to make the 1/2 mile loop on 4-5 gallons. So I am told. Another good point is even at 3:1, alky is still cheaper than racing fuel.

Maybe I should look into an OD trans :)

Good thread though and I can see it helped a lot of guys out. I just got a kick on the fuel mileage part :D

Good luck to ya and have a good one!!!!!!

Auggie (ag460torino)
That's pretty sweet, I'm glad u swapped out that flexplate! The 1/4" plate would have been fine if I didn't have to trim it at all but I trimmed off a good bit but still within TCIs minimum specs.

Well in ur application fuel mileage is pretty horrible. I'm not sure why u went with alcohol vs E85, the latter is cheaper and has a pretty high octane rating. Either way they both require more fuel to be consumed.

I really like the idea of the GV unit, but on the C6 u need to remove the output shaft to use there own output shaft. So that requires complete disassembly of the trans to do the swap. Plus they still don't have a lockup. But if I was building an all out crazy racer and wanted more gears I would def go with the GV unit.
 
#77 ·
Custom my truck has been sitting on the hoist for month... I changed converter and had a used billet converter from a friend rebuilt... the The rebuild did not work out no TCC lockup wont work... Called the converter company and they said they would sent out a new converter... Got the new converter and the bolt pattern was wrong contacted the converter company and he said he would send out another converter haven't receive it yet should be here tues... this converter up grade has been a pita. but cold so I got all winter...
 
#78 ·
Sounds like none of the new converters are locking up... How can that be? I mean I find it mind boggling that all these converters and most new that just don't work... These ppl do build converters for a living right? Lol.

Are you sure your trans isn't the problem? That would make the most since none of the converters are working. Did you replace or check the oring on the end of the input shaft? Is the lock up solenoid functioning correctly? Lock up wiring?
 
#82 ·
On a side note I made the decision to go with EFI. Thought about selling the carb stuff to help with costs but prob wont just in case I decide I want to back or use on something else since its only got 500 miles on the stuff and I would loose too much trying to sell it.

Going to go with the base fast EFI 2.0 system, modify my stock distributer (if it doesnt work i will have to buy there distributer which is like $347). Im also going to use a -6 feed line and keep my original -10 return. The -6 feed should support 650-800hp so im cool with that and It helps keep costs down. I just purchased a Accel DFI fuel pump that flows 70GPH at 45psi and is rated to 875hp and got it for pretty cheap. This should bring my EFI total swap at alittle less than $2600 total without their distributer.
 
#84 ·
So out of curiosity how much do they charge for a driveshaft like that?

D


Sent from AutoGuide.com App
 
#86 ·
Right now they are having a sale, normally they are $475 fully balanced, spicer yoke, spicer solid 1350 u joints and 3" "secret steel" and they are unbreakable. If you break it they give u a whole new shaft free. They are on sale for $445 but I paid only $380 bc I already bought the slip yoke from them to set up the trans so they deducted it from the price.

Edit: heres the site listing for the nitrous ready driveshaft http://www.dennysdriveshaft.com/c1_nitrous_ready_driveshafts.html They have great customer service and denny is a cool guy.
 
#93 ·
Well i finally got some time to work on the car due to snow. I installed the driveshaft to check that the trans is centered in the driveshaft loop which it now isn't ugh. I want to say its less than 1/2" from the top of the loop but more like 1" from the bottom. The rear suspension isn't fully loaded yet either so thats why the slip yoke is that far out, should go in about 1/8-1/4" more when fully compressed.

I fabbed up the new transmission cross ember, this time I used a stock trans crossmember and added a 5/16" plate for the mount and then used some small gussets to reinforce it. Afterward the crossmember was cleaned and painted with POR15. This was much easier than tabbing my own like the C6 required. And there was no way to get the C6 bracket to work in this application. You can also see how far i have the trans pushed back compared to where it would be stock (firebirds came with 700r4 and 2004r transmissions.

In order to gain some more clearance between the driveshaft and the loop I used some washers to space the crossmember farther away and then used the trans mount bolt to bring the tail of the trans down. My trans is fully suspended and hangs off the back of the block with no trans mount due to the tight fit with the BBF and the BBF headers.

So the trans is basically all done. Just need to wire up the speedo sensor, temps sensor, kick down cable, shifter cable and brackets and run a 12V to the lockup connector and fill it up with fluid. Got about 3-4" of snow today so won't be till april ish when I can get the car out to test the new trans setup. Which gives me plenty of time to swap to EFI and finish all the odds and ends.
 

Attachments

#94 ·
(quote) In order to gain some more clearance between the driveshaft and the loop I used some washers to space the crossmember farther away and then used the trans mount bolt to bring the tail of the trans down. My trans is fully suspended and hangs off the back of the block with no trans mount due to the tight fit with the BBF and the BBF headers.
(quote)
Trans mount,no trans mount...Not sure where you're going here.Looks like a trans mount.

Unless that yoke is a foot long or the shaft really pulls up with the suspension loaded,your drive shaft is too short IMO.With a slight out of balance and those big ol 1350's spinning,it will eventually wallow out the splines,taking the bushing and seal with it.Been there.Or it might be fine,depends on the condition of the yoke and the tailshaft.

You are gonna love that EZ2.Ran into a guy I know with a big inch FE,couldn't keep it running for at least 5 min after starting on an 80 deg.day.Went to EZ,starts and runs perfect right away,put it in gear and take off,on a 20 deg.day! I'm sold.Keep us posted
 
#95 ·
ALittle confused here. The rear of the trans has somehow tilted up alittle too much during the swap, causing the driveshaft to not be "centered" in the driveshaft loop as it was before. Its closer to the top of the loop, so to compensate I lowered the trans mount to pull the back of the trans down to center the driveshaft more in the loop.

How is my driveshaft too short? Its 51.5" long and the max length for a 3" DS is 55" otherwise I had to step it up to a 3.5" shaft. The whole shaft is balanced to like 9K RPM and comes fully assembled so the balancing stays intact. Yoke is a brand new Spicer slip yoke, and tailshaft is original but in good condition splines looked fine. This trans was behind a 170hp 305 SBC for its life so its very little strain on the trans parts lol.

Reason I was worried about the driveshaft being centered is that when I hit the track I swap the rear tires out (has 26.5" tall street tires 315/45/r17) and swap to MT radials 295/65/r15 which is a much taller tire. But by doing so I need to extend my rear suspension to compensate for the height of the radials. So i had put in weight jacks in the back springs which is basically a screw that extends the rear springs upwards to adjust ride height kinda like a coil over. This allows me to get the clearance for the taller radials. I was worried about suspension compression and the driveshaft rubbing on the top of the loop. I should be good to go.

Im going to start a thread on the EFI swap, I already got the new fuel system run for the EFI up to the motor. Just need to purchase the EFI which is like $2300 and I will prob go with there dual sync distributor so that puts me at like $2650. I would modify my dursapark but I've heard of lots of probs getting them sync'd right. Can you find out more info on your friends setup? did he run a stock distributor? MSD or FAST?
 
#99 ·
I was only wondering bc that same model/type distributer would work in the 460 version from MSD. You can convert all mag pickup distributers but u need to remove the reluctor roll pin and drill and tap the reluctor wheel for a set screw. Then set timing so its some number FAST wants so the ECU knows the timing. They said even if you do it 100% correct that there is still a 50% chance it won't run right. And Ill end up buying FASTS plug and play distributer anyway. He said that ppl usually try to modify the MSDs and he doesn't know the duraspark off hand. But the MSD distributers are like $250+ anyways and FAST sells there's for $340 and its plug and play.
 
#100 · (Edited)
Yeah,I guess I would go for the FAST dist too.But....in all the vids I saw on dyno pulls,hp comparison to EZ1,carb,there was no mention of the dual sync being used except on Frieburger's Super Bee.I assume the unit was given to him and his pitch for their dist was about the same as the factory site,more accurate timing.While this might be true,I'm going to be pissed if I find out later that the stuff I..and you.. already have works as good and we threw our cash away on some marketing ploy.
The friend's dist is a MSD 8594.It works great and He's no electronic genius,that I know.I'm one of those guys that have to be convinced.They have till spring to do it.
 
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Top