360 build and A999 question

Posted By: JoesMopar

360 build and A999 question - 10/04/12 05:54 AM

Will an A999 live behind a "mild" 360? The car is a police package Diplomat. I'm wanting to keep the A999 so I can reuse all my stock linkage and also have the lower 1st gear ratio.

I'm just wanting to drop in a budget 360, nothing special, just a fun sleeper. Any tips on a "decent" 360 build in the ballpark of 300-350hp that you guys recommend? I don't want to go the Magnum head route as I already have an Air Gap intake and don't want to redrill it to fit the Magnum heads. I was thinking of some decent closed chamber heads and flat top pistons but was wondering what you guys suggest.

Thanks.

Posted By: scratchnfotraction

Re: 360 build and A999 question - 10/04/12 01:25 PM

thats what would come behind a 360 in a cop car.IIRC

thats what I got out of an 87 dippy cop car with a 318 also.

depending on yr it may or may not be lock-up trans.

I swaped in a stock high stall lock-up TC on mine.

holding up fine in my daily driver 85 stepside roller cam 318

a pre-mag roller cam 360 would be a good start for a bottom end.

you can get magnum heads with the LA intake bolt pattern.

2nd choise is run a stock set of 360 heads

Posted By: Greg Ducato

Re: 360 build and A999 question - 10/04/12 02:04 PM

That is a great little trans and will do well behind the mild 360 you plan. You will need to build the converter though and have a balance weight added or use a special flexplate to provide the proper balance. I think the converter is the achilles heel of this transmission but once properly built is quite good.

Posted By: RapidRobert

Re: 360 build and A999 question - 10/04/12 02:46 PM

Quote:

Will an A999 live behind a "mild" 360?

Yes but as said be aware I think it'll be a lockup and the converter drive hub is the weak 904 point but at your power level I doubt you'll have an issue. Yes some mag heads with the LA pattern or possibly some ported/bigger valve 302's for the closed chamber. I would shoot for .040" quench (with the appropriate scr also depending on your fuel/cam choice) for a much more efficient eng. this'll let you run the most CR and ign advance on your choice of gas & with todays fuel quality that is critical.

Posted By: JoesMopar

Re: 360 build and A999 question - 10/04/12 04:47 PM

It is a lockup converter, but I didn't know that was the weak point.

Thanks

Posted By: dogdays

Re: 360 build and A999 question - 10/04/12 06:01 PM

It's the converter drive that's the weak point, and not the converter. They have a tendency to crack from the corner of the slot, when the part breaks off it's a mess.

Having said that, hundreds of thousands of 904s and their derivatives like the A-998 and A-999 have seen service behind some pretty stout smallblocks without failure.

I'd call somebody like CRT and see what they say. Buy their parts and put'em in.

BTW, if your 904 family trans came behind a 318 it's an A998.

R.

Posted By: JoesMopar

Re: 360 build and A999 question - 10/04/12 07:59 PM

From what I understand about police package cars, 2bbl cars got the A998 and 4bbl cars got the A999. Mine is a 4bbl ex-THP car

Posted By: scratchnfotraction

Re: 360 build and A999 question - 10/04/12 08:33 PM

Quote:

From what I understand about police package cars, 2bbl cars got the A998 and 4bbl cars got the A999. Mine is a 4bbl ex-THP car

I think this is correct,my 88 4-v 318 had it and the 87 4-v 360 had it. the last 2-v 318 one I had was the A998.

my local trans shop orderd mine with a better clutch band material in the TC added more springs and a drain plug.

you feel it when it locks and unlocks thats one thing I know for sure.

when at WOT and speed is up it is locked up when it nails 3rd. stock ones dont like that at all so it well worth ordering HS heavy duty lock up TC IMO

you can also block the LU valve on the VB and order up a stock HS with the lock up guts removed. I ran this combo also before with no trouble from it.