Transmission section for engine swap

-
B

bblock383

Well-Known Member
Joined
Jun 25, 2011
Messages
105
Reaction score
0
Location
missouri
Ok since I didn't get much info from the early A section I'll ask here. I'm doing a 360 swap in my early A and it came with a 84 727 from a truck. I assume this is a lockup converter transmission and doing the research it seems like it would do better with mileage but not sure about how it will affect performance. My question is, I'd rather use a 904 on this engine for obvious reasons like lower weight, less hp loss and just a better fit in my early A. Don't really want to beat my trans tunnel up or have my drive shaft shortened. But I'm getting conflicting reports on whether a 904 will hold up behind a 360. It's an 82 360 with 88k miles, only mods are Stealth intake and Edelbrock carb as far as I know. My understanding over the years is the 904 will handle 500hp without needing to be toughened up or switched to a 727. Is this not correct? I don't see myself making 500hp with this engine unless I go turbo or tear into the engine for more compression. So bolt ons is going to be the extent of it. So what's the answer? Anyone running 904s behind 360s?
 
Not sure what forums you've been reading; I've got to laugh at the haters most of these rumors are perpetuated by people who know nothing about the inner workings of these, or parroting someone else.

The bottom line: If an a904 can't hold a 408, let alone a 360, it isn't built right. It doesn't take much. They are very simple to deal with, one of the, if not the easiest auto trans to rebuild.


Hop on google and do a 'a904 beef-up' search.

One of many advice threads:

http://board.moparts.org/ubbthreads/ubbthreads.php/topics/1004715/2.html


Ask 70aarcuda, he has several dusters in the 10's with a904s.


Fishy68, and trailbeast are also very knowledgeable. Go forth and build! Be sure to get a good converter and a big cooler!!
 
I've got a 68 904 that might be in good shape from an old project. Will that transmission work on my 360 without having to beef it up? My swap budget isn't enough to include a beef up of a transmission. Now Ive heard to beef up a 904 I can use certain 727 parts so maybe I could do it that way? Would be free. Is a lockup trans a bad choice for performance? It's better for mileage I understand.
 
I've read (in numerous places) that 71 and newer 904's are tougher than 70 and older units. Now on the 904 holding 500 hp without mods, I do not agree mainly because there were variations of the 904's. Some only came with 3 disc clutch carriers and 3 pinion aluminum planetary gearsets. IMO those are only good for about 350 hp tops, and that's if you add a good shift improver kit. 904's with at least 4 disc carriers and steel planetaries are what you want to hold a lot of power. The lockup trans won't hold as much power either because of the hollow input shaft. Not positive what to rate it but I wouldn't feel comfortable with more than 400 hp in front of one of them. Nothing except the valve body and speedometer gear and adapter and bolts from a 727 will work in a 904 and to make a 727 VB work in a 904 you have to swap the 904 parking pawl onto the 727 VB and elongate one of the mounting holes in the separator plate so it aligns with the 904 case. Whoever told you 727 parts work in a 904 doesn't know his butt from a hole in the ground
 
I think it is a 72 or 73 newer 904 is what you want..the front servo changed for the better...I remember Turbo Action actually had a casting number they recommend to start with...I mean nothing older then it.
 
You must log in or register to reply here.
-

Back
Top