Slant 225 Paired With an a904

[zmarty27]

Morning, everybody.

I'm prepping a rebuild on a 904. I'm not entirely sure what I want to do just yet, but what I do know is that I want it capable of future performance upgrades and modifications. I want this to be rather quick on the street. If I wanted to run it wide open on a track, I want to be able to do so, but I wouldn't do it regularly. Honestly, that may never happen, but I want a reliable transmission that could do the trick. I want this to be a daily driver if possible, but fuel efficiency isn't my main concern. So far, all I have done to the engine is port the head, milled it .010", and put on a Carter BBD. Future plans include upgrading the exhaust system (Dutra Duals), and further down the road, milling the block (amount milled TBD). Eventually, I'll have a higher compression ratio than the compression they had in '74.

With that said, I want this to be a sleeper build of sorts. I'm simply lacking a bit of direction. Endgame is a car that can run a modest 14 or 15 second quarter mile with the Slant. Currently, I'm stalling out at 80+mph (basic rebuild on the current 904 was done with OEM parts aside from the billet accumulator). I don't routinely put incredibly high rpm stress on the engine, but I ran it as fast as I could after the recent 904 rebuild. Same stall as before with the stock a904. I have the stock 7.25 rear end. I'm willing to replace that to a beefier rear end if necessary.

Thoughts? Do I need to include more info to help? Just curious to see what recommendations/do's/don't's are out there.

Thanks!

 

[halfafish]

So far, all I have done to the engine is port the head, milled it .0010"

Is this number correct or maybe a typo? One one-thousandth of an inch amounts to about nothing if you're milling the head to increase compression.

 

[zmarty27]

Is this number correct or maybe a typo? One one-thousandth of an inch amounts to about nothing if you're milling the head to increase compression.

Went crazy with the 0's. It's corrected. Thanks for catching it!

.010" isn't much in the scheme of things. The head was a little warped from years of running hot.

 

[junkyardhero]

you're running a slant, so i wouldn't be too worried about thrashing a trans behind that-- you'd more likely blow up the rear end before killing it.

once you've decided on the aspects of your build-- namely cam and gears-- select an appropriate stall converter and throw a shift kit at it and call it done. keep the fluid and filter changed regularly and it'll live a long and happy life.

 

[MadScientistMat]

Right now I have a Trans-go shift kit and a beefier band strut in an otherwise stock 904 behind a turbo 225 build. Not too many miles on it and no dragstrip passes or running slicks yet, but I'm not too worried. I did swap the 7.25" axle for an 8.75" though.