Maybe you can help me spend the next money I don't have yet (PLEASE don't tell my spouse). I'm wondering what's the best return on investment for my 69 Malibu. Here's the set up: 350, about 9.6:1 CR, mild performance cam (218 deg and .454 at .05"), 600 cfm carb, stock single exhaust, stock TH350, 2.56:1 12 bolt rear gears.

I can do ceramic headers and dual exhaust for around $600, or switch to a 3.42 or 3.73 gear for around $800 (assuming my rear axles are in good shape). For torque/acceleration and life under 4000 rpms, which is the best bang for the buck?

On a related note, how liveable are 3.73 gears on the highway with a TH350 transmission? I played with a gear ratio spread sheet and found a pretty big difference in RPM from my current gears, but would like to hear some real world comments.

Thanks for any ideas! graemlins/hurray.gif

I would do the gears and get a $159 2.5" exhaust from Jegs (complete w/mufflers) and pair of non coated headers from Summit for $79

Why $800.00 for rear gears? That's alot of money. There are plenty of good used gear sets around. 3.73's are available all the time. You could even go with a 3.31 for a big improvement over the 2.56 and be happy with the highway manners. 3.31's are around used for about $50.00/set.

$800 is a quote I got from a drivetrain shop for parts and labor to install new gears and limited slip diff. The posi unit and gear set new from Summit or Jegs is about 600. I'm thinking this project is over my head, I'm a bit greeen. Does $200 for labor seem about right?

thanks-Dave

Headers and dual exhaust. You are choking that poor engine with a 2" single exhaust, especially with that single pattern cam on a 110 LCA. I would not be surprised to se a genuine 25-40 hp from an exhaust swap.

Dave,

$200 is a more than reasonable price for setting up a 12 bolt posi. Make sure to spend the extra bucks for a new bearing set if that's not already included in the price. I highly recommend an Eaton differential. I've been beating on mine now for 5 years and it still works great. I'm using the one with 400lb springs. They make an even heavier model (800lb springs I believe), but it's neither needed nor would I recommend it for a street car. Depending on how far your going with the gear change you may be able to find a 3 series gear to work with your 2 series carrier. I have a 4 series gear in my stock 3 series carrier. The ring gear is just a little thicker (and stronger). Do not use a spacer to accomplish this.


my $0.02

be careful when you select your gears. If you go to low you'll might skip right through your power band.

I put the 800lbs springs in. Don't have any problems on the street. Maybe my exhaust is too loud to hear tires dragging and clutches popping, though.

Tim.

I run 3.73's with a th-350 and it isn't that bad though I do find myself in the slow lane alot. 3000 rpms is about 65mph. If your wanting to do alot of driving I'd go for some 3.42's, that would make highway driving a little better but you still can get a good kick in the pant's when you romp on it. ;)

As for what I would do if I was left with your choice I would go for cheap headers - exhaust and gears. Cheap out on the exhaust and go back to it later. You'll glad you did. :D

Dave,
just my opinion but i say gears all the way! my velle has your everyday edelbrock intake and holley carb along with dynomax "black-jack" headers and cheap-o 2 1/4" exhaust. with my 2.56 gears i could barely notice a difference when i put any of those on! However it did cruise along below 2000 rpm at just about any speed and it knocked down a worst of 17 mpg most of the time. so i guess it depends on you kinda?

sorry i forgot to mention it was a 355
Jay

Dave,
$800 seems about right for new gears and posi. Your gear man is probably going to suggest that you purchase new axles as well. $200 dollars for labor is actually pretty good for labor. I went from 2.56s to 3.73s and dropped about half a second just in the 1/8th mile. It was a huge difference! Then again, your car will sound just like another grandma car without the exaust. I cruise in the slow lane on the freeway, but its worth it.

Dave,

A little misunderstanding. I didn't catch your any mention of adding a new posi at the time of gear change. So you will definitely have a money issue. Not for anything, but there's nithing wrong with running an open rear. That's a 400 swing in you expenditures. My '69 SS came through from the factory with a 3.31 and an open rear. It was driven that way for 34 years and 86,000 miles with a 396 and an automatic. If money is tight, you have to make compromises. If all you re doing is drag racing or going out to lay rubber at every stop sign, then drop the money on a posi. But if general cruising and highway running are the plan, don't spend the money on it right now. Seems to me that you want a nice driveable performance increase. Email me if interested, I might be able to get you some nice used gears for a reasonable cost.

I say buy the summit exhaust kit and headers and see what Toms Differentials can do for you. You might be able to get both!

Well we have $159 2.5" exhaust from jegs,$79 uncoated headers from summit,choose rear gear of your choice,and go the route of mc71454 powertrax (http://www.jegs.com/cgi-bin/ncommerce3/ProductDisplay?prrfnbr=2006&prmenbr=361)

Dave, Are you sure you have a 12 bolt housing under your Chevelle? Most small block cars have the more common 10 bolt. (count the bolts around the rear end cover plate to be sure). In any case the headers and dual exhaust will be much more beneficial than the gears and will increase your gas milage too. There are some good mandrel bent pre-made exhaust systems on the market. Talk to lots of people and see if you can find a system you like before buying. Shop around because $600.00 sounds a little high. Borla makes the best mufflers but they are pricey. though.

There's a shop on ebay that deals with rear ends and will set you up with a Eaton Posi unit, Richmond gears (any gear ratio you want) and a master rebuild kit (bearings, gasket, shims, everything) and its just a BUY NOW click, NO Tax for only $579 :D If you need me to send you the link, Just email me.

As usual thanks to everybody for the info. and opinions. Learned something as usual.

Dave, Did you count the bolts around the rear end cover plate?