[BILL TIRELLI]

HI GUYS, my 69 SS396 -375hp has a 4sp and 410 richmonds. The 410`s really make her rock but last summer I went to a lot of shows and did a lot highway driving. Cranking 3,200 rpms at 55 mph starting to get old. Want to lower those rpms but still have some pop. Which gears would be middle of the road, 355`s or 370`s with my motor and trans. Thanks.

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BILL TIRELLI TEAM CHEVELLE MEMBER#280 1969 BLK CHEVELLE SS396 375HP 4SP 410 POSI
STATEN ISLAND NY

 

[plain 69]

When we traveled to Pigeon Forge in my Dad's 67 SS 396 with 373's, with 4-speed. It was turning about 3100 rpms at 60 with 245 60-14 BFG tires. I think they are 25.5" tall. We cruised a lot at 70mph at 3400 or so. We wished we had 3.55's. We will be heading there again April 14-16 for the Grand Run which is a show for everything 1950 and newer. Never seen so many cool rides. Floyd Garret running around in his ZL-1 67 2 door sedan, that was cool. 3.55 gears are good with the stock cam and cruising distances.

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Malibu 307 (aka 406 smblk)
69 SS 396(aka 454)
Wolf in sheeps skin

 

[Tom Lasater]

Bill, either one of those gears will slow that motor down on the highway, but tire size plays a role in your selection. I have 3:73 gears in my 69 SS and when I take that car on trips I "borrow" the R235/70/15 tires off of my "Formal" Chevelle because with taller tires it also slows the motor down. If you are running tall tires and the rpm is annoying, I would recommend the 3:55 gears. The POP will take care of itself!

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69 SS396 69 Malibu Ragtop
70 Monte 72 El Camino
Team Chevelle Gold #33
ACES Member #02913
Chevelle Club of Michigan
Rode shotgun in the ONLY Z16 convertible made.

 

[drptop70ss]

I would also recommend the 3:55s if you run 15 inch tires, that should lower highway rpms quite a bit, and you can always go with 14 inchers for around town fun. I usually run 3:73s max with 15s and 3:55s with 14s, but this is with limited highway use...then again how about overdrive and leave your gears alone??

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70 chevelle ss396 conv
66 chevelle ss396 hdp/conv
55 chevy prostreet

 

[lindsay]

I've got 3:73's in my 71 with a 406 small block. 28 inch tall tires and turn 3400 at 70 Mph. I like the zip but don't like the high RPM at highway speed. If your car isn't completely stock I would consider investing the money in to an overdrive tranny like the new T-56 six speed. Then you would have the best of both worlds.

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[Gene Chas]

Bill, the only thing I would add to these excellent replies is be careful about going too high depending on which 4 speed you have. A M21/22 just don;t like tall gears. I have 3.55 and pretty tall 28" BFG Drags' and the M21 1st gear just don;t cut it with my mill. BTW, I spin at about 3000 going approx 68. Not bad.

 

[Tom Kordick]

I agree with Gene. If you have a M21 or M22, 3.55 would be the highest to go with otherwise you will really have to slip the clutch to get going.

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