Switching up a DRM 385

[Zman]

I currently have a DRM 385 with 4:10's and upgraded brakes. I'm thinking of switching back to 3:45's with a 22lb flywheel. I'm also adding DRM coil overs. Does anyone support this setup or suggest a different gear ratio or a different weight flywheel. I just sold a Henderson 368 with coil overs, 4:10s, and a 13.5# flywheel. I'm trying blend these two together per say. Give me some feedback?

[Mikey]

I'm not really sure why you sold the 368, but THANKS!

[Zman]

It all came down to sound. The 368 sounds like thunder going down the road and required ear plugs. My 385 sounds like a jet engine no ear plugs required. That was the deciding factor. Sold my house, new house has 2 less spots to park. The last owner was generous to me, so I passed it on! Enjoy your Henderson 368!

On a side note I decided to go with 3:78 s in the 385.

[Zman]

Current path: 22# Jerrys Gaskets?s flywheel, Dana 3:78 gears with correct speedo gear, and DRM coil overs.

[rkreigh]

Originally Posted by Zman

Current path: 22# Jerrys Gaskets?s flywheel, Dana 3:78 gears with correct speedo gear, and DRM coil overs.

great choice. the stock gears are a bit too tall to make 5th gear work well on highway. Even with the stroker and more torq, with the lightweight flywheel the car has less inertia to get the car moving so that gear will work better. The 385 is a great engine, enjoy!

[Zman]

New car in the stable! DRM 385CI, 3:78 gears, 15 lbs Aluminum flywheel with dual disc clutch, DRM coil overs, Pete tuned the car for 93 octane after installing everything. Very impressed with this set up. Wow!

[Hib Halverson]

The stock axle, during development a 3.54, but virtually all of production a 3.45, was picked because GM wanted the car to have a top speed of 180-mph in fifth gear so the ratio was selected such that, at the engine's power peak, it would be going about 180.

A good 368 or 385 is going to not only make more power but will likely have a higher power peak, so the car could still make 180 but with a slightly lower axle.

When I owned Barney, it's Automasters "Street Skinner" 350 made about 505-hp and 413 at the tire, but it did that about 500-rpm higher. My "plan book" always had a change to a 3.73 or so axle ratio listed. I'd have gained some acceleration and maintained the coveted 180-mph top speed. Never got a chance to do that.

Also, Barney had a McLeod aluminum flywheel and I never had trouble driving that with the car's stock 3.45 axle ratio. "rkrieh" seems to think there's a problem with an aluminum wheel and the stock axle, but, in 20 years of driving Barney in all kinds of situations, I never had trouble.

I have aluminum wheels in both my C5 ZO6 and my C6 ZO6. Both cars have stock 3.42 axles and I have no problem driving them.

[EvanZR1]

I had 4.10s on my previous ZR-1 with just top end porting, and it really woke the car up. I think the 4.10s are great on stock/near stock ZR-1s, but are too much gear for anything over 500HP and probably borderline even for that 500HP.

On my current 391 cid ZR-1, I have the stock flywheel and 3.45 rear and I'm very happy with the setup. I ran 176MPH in the standing mile (before final tuning was even finished, which gained me another ~25HP), so I'm pretty happy with it. Ideally with a shorter 5th or overall numerically higher rear I might gain a little bit in the mile, but then I'd sacrifice elsewhere (1/4, 1/2, street, etc). With the current ratio, 5th for me would top out at 220MPH, so a 3.78 rear would probably be better as it would top 5th at 200MPH (doable with my 391 on a long enough straight), and it would make 6th a little more usable (even with the 391, cruising at less than 80MPH in 6th seems sluggish). But that's a fair bit of money for a minor change, so will probably just stick with what I have.

If I were you, for a 385cid with 4.10s, I'd probably drop to a 3.7x gear and stock flywheel.

[Zman]

Originally Posted by EvanZR1

I had 4.10s on my previous ZR-1 with just top end porting, and it really woke the car up. I think the 4.10s are great on stock/near stock ZR-1s, but are too much gear for anything over 500HP and probably borderline even for that 500HP.

On my current 391 cid ZR-1, I have the stock flywheel and 3.45 rear and I'm very happy with the setup. I ran 176MPH in the standing mile (before final tuning was even finished, which gained me another ~25HP), so I'm pretty happy with it. Ideally with a shorter 5th or overall numerically higher rear I might gain a little bit in the mile, but then I'd sacrifice elsewhere (1/4, 1/2, street, etc). With the current ratio, 5th for me would top out at 220MPH, so a 3.78 rear would probably be better as it would top 5th at 200MPH (doable with my 391 on a long enough straight), and it would make 6th a little more usable (even with the 391, cruising at less than 80MPH in 6th seems sluggish). But that's a fair bit of money for a minor change, so will probably just stick with what I have.


If I were you, for a 385cid with 4.10s, I'd probably drop to a 3.7x gear and stock flywheel.

The current set up is 3:78s with a 15lbs aluminum flywheel. I really like the faster rpm acceleration with the lighter flywheel. I really like this setup while driving alone. I have noticed that with an added person in the car the transmission rattle is a bit louder. I?m very happy with the set up. I wanted a 22lbs flywheel but Jerry didn?t have a clutch kit with that weight flywheel.

[wfot]

I am planning a 402 build. Curious as to what the bore/stroke is on the 385?
any audio or video of it? not many 385s out there?

thanks
john