Rear end gear,RPM,reartire height info

Forums Forums RACE TECH QUESTION FORUM Rear end gear,RPM,reartire height info

Viewing 9 posts - 1 through 9 (of 9 total)
  • Author
  • #10170

        I’ve been looking at some drag cars, maybe gonna buy one, and I’ve got some questions. The car that interests me the most is a MONZA. It was an old PRO car, all glass except main body panels, pull off nose etc. The car has a 421 sbc engine, 14:1 compression, and runs on racing gas. 2spd glide with a brake, 5:14 gear, and a set of 32x15x15 rear tires. This car has only run 1/8th mile, never 1/4 mile. Two things. I want to run it on alcohol, which likes compression, burns clean, cool, and used to be about half the price of racing gas, and do you think a 4:56 gear would work better. The last time I drag raced was 1977, after that until a couple years ago it was circle track. Oh, the owner said the car always ran mid 5s in the 1/8th on an easy launch, and he never pushed it. Well, what do ya tink??
        Mikey 😮 😯 😆


            Mikey you should be able to run it in the 1/4 the way it is. You just have to find what it revs to and the power band of that motor. But those gears and tires are in a lot of SBC motored race cars.



                Thanks for the input Pat, I appreciate it. 😀 I actually ran BBC engines with that gear, and 5:38s too!! I’m not concerned with over-revving, as much as just wearing it out. I don’t want running it a couple of times a month to run into high maintenance. I don’t want to be constantly checking bearings, rod length, et., etc. 😀 I just want to have fun, raise a little hell, and scare the crap out of myself again. 😈 😈 And always remember, “You can’t beat fun for having a good time”!! 😆 😆 😆 😆 ……………………..Mikey 😮 😯


                    Mickie at 7000 rpm 5.14 gear 32.0 tire about 130 mph at 7500 about 139 but you also have to take tire growth and converter slipage usually about 5% into consideration. Hope this helps.


                        Ok …Heres the deal…Get It …Put M&M Speed on It …I’ll send ya the lettering ….Name -Dover Stuff. Take it out to Palm Beach…Get old Dover Guys to be Bald, overweight ,near sighted pit crew….Florida has plenty. Shake it down…then Come up to Nostalgia Drags .Follow Blake…He knows the way. And remember….Where ever ya go, there ya are.


                            Run it the way it is now then you’ll have a blueprint to work with……..Don’t spend money for changes until you know what it does ……rpm @ shift points, rpm thru the traps, how is it leaving etc. etc….I ran 6:17 gears in a 2900 lb. car with a 354 smallblock and everyone told me I had too much gear…When I did go down just another gear, 5:86 I lost almost a tenth….There is a base for all but everyones car is different………..Do yourself a big favor and run it first………….Don Kauer….


                                I really appreciate the input from you guys!! If I decide on this car, I’ll run it with the gears it has. 😆 Now, what about the fuel?? Alcohol, or gas?? 😮 😯 😕 …..Mikey :geek:


                                    Honestly I dont think you will make more power with alcohol . I use in my car runs cool and it is pretty consistent but that,s with fuel injection. If you are running a carb you will have to get a carb set up for alcohol and you will also need a real good fuel pump to keep up with it .You will burn twice as much fuel .If you get a chance go on bracket talk forum you can get a lot of information on that site .


                                        I’m pretty familiar with alcohol, I ran it in my dirt circle cars, and I built several carbs after I bought a Bolaws Alky carb years ago. It was not that hard to duplicate if you new Holley carbs pretty well. The trickiest part of the deal was changing the jetting and power valve to get the engine temp correct, and not have the engine stumble on hard acceleration. I ran a Carter mechanical pump, with 1/2″ line from the fuel cell to the pump, turned the BBC 7800-8200 RPM, turned the SBC 8000-9000 RPM, and sometimes a little tighter. 😀 😀 I have also read a little about a toilet bowl (trade name?) alcohol system. I really disagree with you saying it wont produce more power, It does!! 😆 But, I appreciate the input, and I intend to pool all the answers and suggestions, and make up my mind on gear, tire, fuel, etc. no matter what I decide to purchase. 😀 😀 …………………….Mikey 😆 😆

                                      Viewing 9 posts - 1 through 9 (of 9 total)
                                      • You must be logged in to reply to this topic.