Need some advice on next mod. to my 69 Malibu. I want stronger acceleration, but hesitant to give up my highway gearing in the rear end. It's a factory 350 bottom end with aftermarket everything on the top end except for the heads (76cc 441 castings milled down to about 72cc). The rest of the top end is edelbrock carb. and intake, .454 cam with 218 duration at .50. Full length headers. stock TH350 transmission. 2.56 gears in back.

My question is can I get close to the performance improvement of a 3.42 or 3.55 gear by swapping in vortec or other heads? My feeling is probably not, but would like to hear some other opinions? I think the cost would come out close to the same for either option. Thanks for any ideas smile.gif Dave.

I'd go with the gear and a cam swap IMHO

3:55's are not bad for the highway.

Stronger acceleration can be attained by the engine parts swap. On the other hand, QUICKER acceleration will be seen with the gear swap.

Does this help in any way, shape or form?

It's a little of the "apples to oranges" comparison. I guess the real question is, what benchmark are you using to measure this performance increase? Are you interested in a better measured ET, or just want to feel more by the seat of your pants?

admittedly, the only measure I will probably ever use is seat of pants meter. This is a street car that may not ever see the track.

Go for the gear swap then.
I recently went from 2.56's to 3.31's and the difference was night and day

Even with 3.08 gears you'll notice a difference, and with my 350 which had the same cam as yours and a th350 I was cruising 70 at around 2600 RPM or so.

Put in a 700 transmission. The ultra-low first gear will help with the original rear gears, and the overdrive will give you even lower RPM on the highway.

You'll probably have to stop every few hundred miles and empty some excess gasoline out of your tank.

I vote for the 700R4 also..have one of the Bow Tie Overdrive units in my 66. 454 with a Comp Cams 280H, 2200 stall lockup converter and 3.73 gears. Pulls like a mule from the light and cruises at about 2500 at 70. It would be great to put one of these in that car with the rear you have, just to hear your response to the incresed off the line acceleration. Might be a dog on the expressway though. You would barely be off idle at 70 MPH.

Go here and see use the speedo calculator to figure it out.

http://www.700r4.com/speedoCalc/rpmcalc.shtml

700R4 are awesome once you get them lined out, mine was spinning the tires through first (might change now that I put some traction bars on) and still getting me over 20MPG cruising at 70-80 for nearly 5 hours straight.

I smile big everytime I stomp it in first or get a 2-1 kickdown...its more than enough to snap the neck of passengers who don't know better than to put there head against the headrest when they ride with me :D

I'd change the gears to what suits the engine/combo best, after you finish all your engine work. You replace the gears now, change engine parts later, and it might not be good then.

well as off as it may sound i would go for build the motor stronger. make more power. that you can really feel in the seat of the pants. change gears and then blam tire spin. tire spin dont put you back in your seat.

i run 2.73 gears (use to be 2.41) and the feel of you being put back into your seat when you mash the gas is great. i use to have a tire fryer for a street car but the feel of being set back is not the same. punch the gas peddle at 30 mph and just get tire spin....ya sounds cool but not going anywhere. punch the car at 30 mph and being plastered in you seat ...now thats better... i would say build the motor for all kinds of power you can get.

even tho my car only runs 13.50's but it runs in weather im on the street or at the track and 107 mph + is nothing to sneeze at. i may not be quick but a 12 second car at the track wont beat me on the street (because most of them are using slicks and open headers....put those street tires back on and mufflers there no longer a threat). while there spinning there tires on the line i will be hooked and gone.

the guys who have driven or rode in my car have said they really like the way it just sets you back in the seat and how hard it pulls. and this is comming from guys with low 13's all the way to 11 second range cars.

so i would say go for more power. if you dont like it then start cheating the gears lower.

Thanks everybody, still not sure which way to go, but have some time to think because I don't have the money for either one yet!

My 3:73 gears are freeway flyer's with P295 50r15's

vortec heads would surely help, but not nearly as much as going to some 3.42 gears and about a 2500rpm convertor, IMO. then do the head swap later and it will help some more without sacrificing anything anywhere else. .02