Hello everyone. My 67 GS has a 12 bolt rear with 4:10 gears with a TA cover. This is how it came when I bought it. I am looking to change the gears now that I am in the process of installing freshly rebuilt 455 engine. It has a 400 tranny. My main goal is cruising around town and at times get on the highway. Which gears should I go with? Thanks for info
Get a 200R4 trans. or a Gear Venders Over Drive & have the best of both worlds. With a Gear Venders that 22% reduction would bring the 4.10's down to a manageable 3.2 ratio.
You're going to get a lot of different opinions on this topic! I like switch-pitch 400's and would keep the tranny if that's what it is. For cruising and highway 3.23 or 3.08 is good. You would have to change the carrier, or change it out drum to drum if you go this way.
What ^^^^ he said, use the $$$ to get a gear vendors and keep the gear you already have! The G/V will give you O/D in every gear making it a 6 speed if you want.
I think before you even think about buying ANY parts...You need to know what carrier series you have 4.10 normally rides on a 4 series carrier which 3.73 is as low as you can go and thery are thin machined gear for this which will be a bid more than the 3 series gear set. If you have a 3 series carrier with a thick 4.10 ...you are all set to go as low as 3.07 ring and pinion. Now you could have a 2 series carrier with a spacer and a thick 4.10 gear set also...NOT likely B UT it is a possibility. What cam are you putting in the 455? If you pick too big as cam duration you will end up with a sluggish low end 0 -3000 rpm 270 duration will make for a monster huge torque output. DO not be fooled by HP is what sells parts but TORQUE is what everyone wants... Stock motors put otu 500ft lbs of torque at 2800 RPM and only 390 HP which is 0ok as I stated you will have 3 gears in the trans to get the job done and you can use 3.31 or 3.42 and have great response still hit the highway with reasonable rpm etc. My opinion and as I always say...It is your car and you will be the final say on everything.
I reused a lot of the high performance parts that were in my 400 engine when I bought it including the 430 heads. The cam is the comp cam mutha thumper cam. I will find out what carrier series is in there once I take the car into shop to get the engine installed.
My vote is also the GV. A touch more money, but best of both worlds. You dont get to have and eat your cake too often. Here is a chance too
And me thinking it would be a simple gear downgrade. Gotta weigh my options as GV is a bit steep. I understand best of both worlds but was looking for just gear change now.
Are you able to do the fear swap yourself???? If so gears, carrier, bearings, gaskets, seals, fluid, new part . 750ish??? Guessing????? Labor. 350ish, also guessing???? So in the area of 1000-1200ish. But dropping from a 4.10 to mid 3 gear is a huge drop and will slow the car down by close to half a second on more in the 1/4 What size tire are you running, with that info you can pretty much closely calculate your rpm at a certain speed
Oh no, not another comp thumpr cam. Summit, jegs, etc should pull that atrocity out of their catalog. All that cam is good for is tricking the buyer into having a slow car Luckily, you have the mutha thumpr, which is slightly less bad
Just toss on some 30X12.5-15 tires and keep your gear the same. Take it easy on the highway and it would be fine.
So about 27.5" tall So 65 should be about 3300 ish rpm now With GV I would guess closer to 2500ish 3.55 should 2900ish 3.08 would 2500ish How cool is GV, have the performance of a race gear set with the fuel economy of 3.08
That's a big cam, it'll like the 4.11 gears. Drop to a 3.42 or less and it'll feel doggy around town. 4.11's are fun around town but on the highway you're limited to around 60 mph unless you put very tall tires on the rear. A better combo would be a milder cam with low 3 series gears.... you'll have more low end torque that will perform better around town and on the highway.
With everything that has been shared, I will stay with the 4:10 gears and focus on putting engine back and enjoying the car. Will reconsider later on in the future. Thanks for all info.
