Okay guys. I need to get my quick change gears squared away so I can get the center section ordered. I need some ***istance. Here's the hardware... ENGINE: I'm running a 331 Hemi (will be bored to 354) with a semi hefty cam, 10:1 (ish) compression and 6-Holleys (progressive) sitting on top. What RPM range should I be shooting for with this engine? TRANSMISSION: T56 6-speed. Gears in transmission are one of the following: 2.97, 2.07, 1.43, 1.00, 0.8, 0.62 (GM/Tremec aftermarket) TIRES: 750x16 = 31.5 inch diameter QUICK CHANGE: Winters V8 center section. My Intentions: I need a set of gears for around town (I expect I will probably never see 6th gear in town) and I need a set for the highway (road trippin'!). The questions... - What RPM ranges should I stay in with that Hemi? (lowest efficient RPM and highest) - What should I select for rear end gears? I found this cool gear calculator site, but since I'm not really sure about RPM capabilities with the Hemi relative to driving behavior I didn't really know where to start. http://www.5speedtransmissions.com/gear_calculator.html Tell me what you guys think! Your help would be appreciated! Sorry for the long post... Scooter
with that spread of gears I don't see why you need a quick change. a low first gear and double over drive. I'd hit somewhere around 3.54's maybe even 3.70
Your ****** situation is different that stock, but ***uming that final gear was 1:1, the original rear gears were 3.33 or 3.55 (apx), so 3.55s shouldn't over rev your engine, & still not hammer your gas milage in town.
I think with the Winters QC the R&P ratios that are available are 4.11 or 4.86. I would go with the 4.11 and then pick a set of change gears that would give you something like a 3.5-3.7 and a 4.5 to 5.0 combo depending on how you put the gears in. With the ****** ratios that you are looking at and the tire size you can run some pretty low gears and still have an overall top gear ratio in the 2.3 to 2.6 range which would really make top gear a cruzer but with 6 carbs your engine may not want to cruze at 1800 rpm. I would also go with the GM version of the T56 as it is closer ratioed than the Viper trans. Just looking at some numbers, if you wanted to cruise at say 2000 rpm at 60 mph you would need an overall ratio of 3.12:1 and with the .62 over drive you would need a 5.0 rear end ratio. So going with at 4.11 ring and pinon you would need a change gear combo that would give you this ratio. Lots of possible combiations and also so much will depend on how "tame" you Hemi is. Rex
Good info and I was wondering about 6th gear and close to idle RPMs. Realistically, I would probably cruise closer to 75 in 6th. Going to play around more. Still wondering about the "red zone" for hemis. Do they like being spun up?
Just fooled around with the gears a bit and it looks like with some 4.11 gears, cruising at 85 in 6th I'm going to be above 2300 RPM With 3.33 gears (if they exist for this rear) that will get me a much better SLR, but real low RPM's in 6th. I think I'm beginning to actually confuse myself a bit. That calculator may be confusing me a bit too. I have not reached a conclusion, but it almost looks like I could run like 3.10 and blast off the starting line, but then run 4.50 and barely be able to leave a stoplight without starting in 2nd... UGG...
in '54 the lower end Hemis had 3.36 ratio, high end (like Crown Imperial) had 3.56. With a 2 speed A/T it probably wound up a bit before that shift!
Seriously though... am I going to pop a cork at 7500 and stall out below 2000 with those engine features? What do you think?
i'm 331, 727 & 3.25 gears but no tach. I'm shure theres someone who knows what a sane max RPM is. At low RPM the extra 2 dueces might be a bit much.
I could be thinking all wrong about progressive linkage, but in the situation of low acceleration, low RPM and 6th gear, wouldn't I be just running on my two primary carbs at that stage? Or am I think upside down, wrong side out and backwards???
Forgot you mentioned progressive, should work. Eventually I'm going to get around to using my Cragar & 4 dueces, will be progressive also.
There's one on Ebay right now with 4 97's on it... Okay, so I'm not totally screwed in the head with the progressive linkage theory? Cool! There's hope for me yet!
dude, your overthinking the issue. Find a set of gears between 3.55-4.3, and call it done, as with that gearbox, you'll have plenty of topend, and quality torque. What were you sticking the driveline in again (just thinking of weight)? Bottom line, find some 4.11's and call it done. Cheers, Drewfus
I agree with Drewfus. When I first got my quick change, I bought about 8 sets of gears. Three years later, I find I only use 2. A 3.89 for daily drivin and a 2.99 for driving to the HAMB Drags. In your case, with the overdrive, I would get a set of 4.11s and 3.25s. Of course, it's all ***ual preference and how you plan on driving the car.... If you drive 50 miles a day back and forth to work, you might want to gear a little on the tall side..If she is an around towner, you can get pretty steep and still be able to handle some highway with out killing yourself. Good luck and please post some pics, I looove quickies. -Abone.
I agree with both of you too! I think too much sometimes... just don't want any regrets. I'm with ya' guys though. Low 3 and low 4 ought to get me what I need. And yes, you guys will get more pictures than you could possibly want! You guys are going to be sick of seeing updates soon... Drewfus... is this junk is being crammed into a Model A...
If you are going with the Winters V-8 Quickchange with the 3.78 Ring and Pinion you could use a # 3 straight cut set, and a # 4 Helicul set and have a noisy set for around town and a quiet set for the highway trips.
in a model A....above is your 'all-rounder' answer, 3.78:1, but I'd just get the helical set purely to let the engine do the talking.....the straight cut gears will annoy you after the novelty has worn off... stop over-thinking and do it, lifes to short. Cheers, Drewfus
I LOOOVE my straight gears. But that's just me....I'm so ******** The only thing I don't like about helical gears is the angle of teh gear teeth make them push out towards teh cover and wear teh cover and cover bearings quicker than straight cut gears would. Nothing too dramatic, just more wear quicker. 4.11s and 3.00s will keep you happy forever, but if for some reason they don't, Speedway has ge****ts for 60 bucks. Ebay is about 25 bucks a set. As long as thay aren't chipped or REEEAL worn, they will be fine. Even a bit of rust pitting won't hurt em. Keep us posted. -Abone. PS. Here is a shot of mine that i have posted a million times..
Scoot ,RPM's depend on how much $$$ you have in the lower end and the valve train and how much maintenance you are willing to do. I don't think I'd push it much more than 5 grand in an "Ex-- Ho-- *****en-- of-- speed " Crusin' is a different game, hows 22-2600 at highway speeds? . To be sure the newstalgia top fuelers push the rpms over 10 grand at times but it takes a billet crank , a girdle ,high dollar billet blocks,roller everything and barrels full of cash in the form of ***. valves, retainers and springs . As I recall ,in the late50s , My 51 Merc. Weighed about 5000 with the early hemi and Cad./La Salle 3 spd. ,it used a solid lifter Howard regrind and 4 97's on a Cragar , stock '54 heads and was highway happy with 3.31 gears turning 8.20x 15s. I briefly ran a set of 4.89s which was OK for the street but ****ed flying low to the beach even at $039.9 for super shell . Tach ? Didn't have the money for no stinkin' tach.
Whew! That was a mouthful buddy! I agree though. Good insight on RPM's. Thanks! The good news is I won't be doin' any racing with this motor, mostly just havin' some fun around town and some road trips. Nothing too serious for this ***embly of ****... Maybe I'll change my mind about that later down the road! Abone, I agree... gears are cheap... which is why I'm going to take Drewfus' advice again and stop thinking about this, get the friggin' rear end ordered, get the damn car driving and just see what the hell it does. Then when the time comes I'll order some more round, ribbed thingies for my pleasure... still can't wait to hear those straight gears. I have a feeling I won't mind too much either!
A T56 and 4.56 gears will still have a VERY reasonable highway RPM. Personally, I wouldn't go any higher than 4.10s. 3.73s or higher will have such a low highway RPM that with your cam, you won't be able to effectivly use 6th gear(I've done lots of T56 gear research because I'm planning to put one in my ex-cop Caprice if/when I need another trans).
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