Ryan Weaver's 1969 Olds Cutlass S W31 Club Coupe - Page 209

**Ryan1969Chevelle** · #**2081** 12-28-2016, 12:58 PM

Cringe away:-)

As far as I know the Chevy rear is the only stronger alternative that is PSMCDR compliant.

Ryan

PS:
Took a little time last night to discuss with Stephen Minore the list of items to go to MASCAR. I think we have everything covered.

PPS:
I even got a 7029250 1969 350 Carb (Non W31 7029255) to use for the PSMCDR engine.

**Ryan1969Chevelle** · #**2082** 12-28-2016, 01:01 PM

Nick Morocco sent the assembly pictures of the M22Z:-)

Those are some strong gears:-)

Ryan

**DW31S** · #**2083** 12-28-2016, 03:08 PM

What 1st gear is in the Muncie? Knowing that will help determine what rear gears to choose. You need some grunt to get that heap moving; trust me, I know all about it. You'll likely need cam specs, rear tire height, trans gears and a guess at trap rpm to figure final gear ratio. I'm gonna suggest a 2.52 1st gear, H70 tires (if they are allowed) and 3.91:1 will get you in the ballpark. You surely don't wanna run out of engine at 1000 or 1100 feet. Get a shift light and start out at 5500 and see how it all feels. I've not run those rules so I have a different set-up, but I bet I'm fairly close.

**DW31S** · #**2084** 12-28-2016, 03:13 PM

I wouldn't say the Chevy 12 bolt is all THAT much stronger---it is SOMEWHAT stronger. The real advantage of using it is the amount of support (both Chevy and aftermarket) in terms of parts availability and tech help from other racers. Tweed, Wayne, Jeremy W. and others (myself included) will tell you that "back in the day", we made do with Oldsmobile differentials......sometimes it was all we had!

**Ryan1969Chevelle** · #**2085** 12-28-2016, 03:30 PM

Thanks Dave,

The M20 (2.56 first gear) that was in the back seat of the car when I got it is all rebuilt. This trans may be used for street, TBD.

The M22 (2.20 first gear) that was in the car when I got it is rebuild. This trans will probably sit on the bench.

The M22Z (3) that Nick just finished is a new gear set with an extra wide ratio. 2.98 first, 2.04 second, 1.47 third, 1 to 1 fourth. This trans is optimized for a reasonable set of highway gears like my 3.42's. This trans will most likely be used for PSMCDR and street duty.

PSMCDR only allows one size up of tires so G70-14 is the largest for me. I will most likely use F70-14's but TBD.

Rear gears are up in the air until the engine is run on the dyno, the overall power curve will be used along with all the factors you mentioned to select the rear end ratio.

Ryan

**DW31S** · #**2086** 12-28-2016, 05:04 PM

Sounds like you're on the right track! Muncie-cubed.......you are the MAN! Hoping to get your water pump numbers tomorrow (12/29/16).

83hurstguy · #**2087** 12-28-2016, 06:58 PM

Olds O-type rears have positively retained axles, which is nice, and aftermarket axles are available. The downside is the limited availability of new gear sets (3.42/3.91 only). Older (some NOS) 4.33 and 4.66 sets are around as not many people use them.

The Chevy 12 bolt is typically C-clip from what I've seen, and the value is higher, so they are more expensive up front once you buy the housing and have new ends welded on for positively-retained axles. But, you have any gear ratio available and plenty of parts availability.

Just remember if you plan to ever switch back and forth you have U-joint differences and a driveshaft length change. I don't see either option being a strength issue for PSMCDR, though I wouldn't recommend being on C-clip axles with a 4 speed car (my opinion, I'm sure 10 people will tell me I'm wrong). There are people that have broken axles on polyglas. I wouldn't worry about it from a purist standpoint, just whatever works better for you. I haven't decided what I'm doing with mine, though I have to decide somewhat soon.

**Ryan1969Chevelle** · #**2088** 12-28-2016, 08:42 PM

Thanks Dave:-)

Thanks Luke:
I agree with your comments, but no opinion? Come on let me have it:-)

Can a 1350 yoke be added to an O-Type?

I like the retained axles, and if I use a Chevy it will have c clip eliminators. (I think there are bolt on kits? )

I will verify total cost either way, but I like that the Chevy is larger, and more HD all around.

Ryan

Postsedan · #**2089** 12-28-2016, 11:32 PM

"I like that the Chevy is larger, and more HD all around."

The smartest thing you've said of this entire thread
[img]<<GRAEMLIN_URL>>/naughty.gif[/img]

Dan

**69 Post Sedan** · #**2090** 12-29-2016, 12:17 AM

If you use C-Clip eliminators....you risk the chance of the axle seals leaking if you drive the car on the street. I'm not apposed to it but that is one of the downfalls and very common.

On a side note.....I don't use them but maybe I'm lucky! [img]<<GRAEMLIN_URL>>/biggthumpup.gif[/img]