3.73 to 4.10 change what can i expect in the 1/4

[406monte]

I am getting ready to yank my little ole 7.5 rear with a 3.73 and and Auburn Posi and put in my 12 bolt with the following.
The 12 bolt has 4.10 with a light weight full spool 33 spline axels and big Ford bearing ends and the tubes welded with a T/A pan on it. I want to know what kind of time change can i expext with the gear change? How much will it drop on the e.t? It is running a 1.78-1.80 sixty and it runs a 12.00's to high 11.90's in the quarter. I have a 3400 stall converter in it. I run 28x12.50x15 ET Streets. What kind of performance gain do you think i will get with this combo?

 

[Blake442]

What kind of RPM's are you running through the traps with your 3.73's?

I imagine you'll see an improvement in your 60 ft. time, but I don't know how much it will knock off your e.t...

 

[custom442]

406 monte - are the hp/tq #'s in your sig at the flywheel or wheels? I'd like to see numbers like yours - low 12's or maybe 11's... I don't want to put out over 500hp on the motor though (2 bolt, cast crank) what've you done to the suspension & rest of the car?

Of course it's a street car that'll be built more for handling so it won't see a strip that much, I'm curious how you built yours

 

[406monte]

Custom442, my numbers are at the wheels. I have built the car for nitrouse just never have sprayed it yet. I studded the entire block and used nitrous rings and head gaskets. The transmission was done by a reputable transmission shop that builds alot of the drag cars around here. I didn't do to much to it just a few tricks to the transmission. As for the chassis istself i have done alot to that. I have Moroso trick springs on all 4 corners, Lakewood Drag shocks on all 4 corners 60/40 rear and 90/10 front. THere is double adjustable upper UMI and single adjustable lower UMI control arms and air bags in the right rear spring. I am running 3.73 Auburn Posi and the rest of the rear is all stock. That is about all i have done to the car and chassis i hope this answers your questions if not then just let me know.

 

[jrm81bu]

Not to be negative but with the added weight of the 12 bolt and the matter of taking more power to turn it, your times may not improve much. Even if they don't it's definetly worth the piece of mind of having a better rear. And of course ya still might be able to pick up a couple tenths. Or more 8)

 

[custom442]

Ya, it answers just about everything. I've been looking around trying to get an idea of what I might run in the quarter. I think after everything's done my car will run high 12's, low-mid 12's with a 50 shot of nitrous that I plan to use. I don't think I'll ever run any 11's on this engine, but plan to swap out the block in the future with a bored 400 sb with similar power as yours. And that info does help for me to get an idea

I've also looked into a 400 sbc with a longer stroke:
http://www.speedomotive.com/s-86-sbchevy-400.aspx
Have you heard of anyone doin this or know anything about it? Would it be similar to a 350, just grind and clearance?

I really like the idea of a 450-455 ci small block

 

[406monte]

Yea, i have read alot about the speedomotive motors and the strokes that they are making. I think that those are insane numbrs for a small block. I don't know how i would trust those motors though. Something about all that just don't seem right to me. I guess i am just stuck in the old concept of thinking. If you have any questions feel free to ask me or give me a pm.

Eric

 

[custom442]

Yea, i have read alot about the speedomotive motors and the strokes that they are making. I think that those are insane numbrs for a small block. I don't know how i would trust those motors though. Something about all that just don't seem right to me. I guess i am just stuck in the old concept of thinking. If you have any questions feel free to ask me or give me a pm.

Eric

okay, will do

I read up some on them tonight, from what I've read the 450/455 stroker kit needs a tall deck block... which the only ones out there that I'm aware of are the LSX aftermarket types (and I'm not about to go dropping that kinda cash on just a block). The 427/434 kit looks solid though, I might go that route for the next build