Almost done with my 412ci motor. Putting her infront of a T-5 and 3.73 geared 10 bolt. Knowing they are both gonna go sooner or l8r i would like to know which gear i should get when i do have to replace the 10 bolt with a 9"/12 bolt. Specs on the motor are

Super Victor Intake
Solid Roller Cam 264/272 @.050, 649/649 lift, 107LSA Advertised Duration was like 300/308 or somethin like that, not 100 percent on it but i am 100 percent on the duration @.050.
AFR 220 Heads
11.4:1 compression.

Now i will be leaving the 10 bolt in with the 3.73s until she goes so this is just for future reference. No daily driving involved strickly strip gearing so ya. Fastest time down the 1/4. Tire size is up for grabs so lemme know what ya think would be a good tire size to match. Gonna be puttin em on some 15x10 drag lites with 5.5 back spacing.

Tranny I plan on replacing with is a TKO600

gearing on that is as follows

2.87 1.89 1.28 1.00 0.82

In a nutshell, would like to know optimum gearing with that motor in mind, that TKO600 tranny (not the T-5) and tire size up 4 grabs. Thanks fellas always a pleasure

 

oh ya if it matters, the camaro is completely stripped (only a drivers seat) no carpet or any other seats, no seat belts (sept 4 driver) no spare, no AC, no pwsteering, no heater. Havent weighed her yet but id like to say somewhere around 3k lbs or maybe a little under. I really have no idea but id say that is a safe bet.

 

If you are only going to use it on the track I would have to say 4.10 at the minimum and if you rellly want to be crazy how about some 5.13.

My neighbour had a set of 5.13 in his 71 camaro. All I can say it used to pick the wheels up off the ground all the way through the intersection. We would also be spinning like 6000 in first doing like 25 kmh

 

Since it's stip only, don't pick a gear ratio until you know what tire size you're going to use.

Stuff the tallest tire you can into the wheel wells then decide what gear ratio will let you cross the finish line at or just before your shift point. 3.73 or 4.10 gears might be ok for 26-28" tall tires but if you can stuff a 30" tall tire in then 4.56 or deeper would be needed.

Red line is not the shift point. Red line is where the valves start to float. My new engine's red line is 7800 rpm. I use a 2 speed powerglide. I shift the 1-2 shift at around 6000 (short shifted) and cross the finish line around 7000 rpm. I currently use 4.56 gears and 29.5" tall tires. At the end of the 1/4 mile the car is maxed right out.

You can use programs like Dyno2000 to determine where the engine makes the most power to determine shift point rpm.

Back in my SBC days I had 26" tall tires and 3.27 gears. I'd shift at 6800 through a TH350 and only cross the finish line in the mid 5000 rpm range because the gearing was all wrong. Swapping in a 10 bolt with 4.10 gears helped with the short 26" tire.

 

If you're strip only and you really want to use a manual transmission, find something different to use. Dragstrip use doesn't need an OD. It's extra weight that's never going to be used. A close ratio 4 speed would be a better choice. We won't talk about high end trannies like a Lenco.

 

I realize that but who makes a strong 4 speed tranny in the same price range that is almost a direct bolt in?

 

Ok fellas lets say a 28x11.5 quick time pro is largest size i can fit in with out tubing and garbage like that so lets use that tire as what i would be running. Once again lets just say I get the TKO 600 (i know its extra weight) but what gearing with that tire size will basically almost max me out in 4th (in my power band 6-6.5K rpm)? As for the 5th gear, i still have to drive to the track

 

Used it already, should be at 6k-6.5k rpm but i just donno how accurate desktop dyno is. Power wise i mean rpm wise heck i donno might be right.

 

 

Is this serious?

That tranny and rear will last exactly 10” behind that engine with those tires on it. I really doubt that you’ll get one serious pass out of them.

As far as choosing the right gear… figure out what you expect the car to run in the quarter, and then choose a gear ratio that will put you at just below your redline in 1:1 crossing the line.

 

And how should i go about doing that (figureing out what i want it to run), person i bought the top end off of said it went 10.7 in a 2800lb chevelle with a 355 bottom end and 13:1 compression with a 4.88 rear gear. I would like to match that if not go faster. Yes my compressions lower but i was hoping the cubes would make up 4 it.

 

Well, you basically have to estimate what the parts are capable of and then temper that with what you’re capable of doing tuning and driving wise.

By top end I’m assuming that you mean heads and intake, donno about the cam (a cam with those numbers are not something that I would choose for anything that wasn’t going to be an all out drag car and even then I wouldn’t quite choose those unless there was something weird with the head flow numbers or your induction that made that appropriate). An all out drag car wound never have a T5 in it and 7.5” in something as heavy as an f-body.

Cubes will make up for the difference in compression if the cam is enough bigger to move the power band up. But then everything else needs to be matched up also, and judging from the little bit of info that I’ve gleaned from this thread and your cardomain site, that doesn’t seem to be the case.

Since I haven’t seen what you’ve got, what you don’t have, how things are put together… and judging from the combination of relatively radical parts + tame parts I couldn’t begin to give you an accurate guess on what hp/times the thing will be capable of. If you want to estimate HP, or how close you think it would be to that chevelle (and give something more like a timeslip with the runs that it’s run) and the weight of your car I could probably give an educated approximation.

 

That cardomain site was probably last updated 2 years ago, as for the tranny and rear end like i said, i plan on replacing them when they go. Just wont buy it till it wont work anymore know what i mean.

As for what i have

400 2 bolt main block 9.025" deck height, 030 over, align bored
4 bolt main splayed caps
3.8" stroke 4340 Eagle Crank
6" 4340 Scat H-Beam Rods
SRP Forged Aluminum Pistons Puts me at 11.42 compression with a .040" quench with my heads/gasket size/ etc etc.
16lb SFI approved Flywheel
8" SFI approved Balancer
Solid Roller Cam 264/272 @.050 / 649 649 lift with 1.6 rockers / 107LSA
AFR 220 Heads
1.6 Roller Rockers
Stud Girdles
Super Victor Intake Manifold
Carb - Pending
All ARP Fasteners/Clevelite H Series Bearings

Thats the set up

 

headers? exhaust? cat back? any flow numbers for the heads (AFR's typically do not flow what they advertize)? Hell, any idea of the expected power band?

The fact is that if you've seen these parts in another car you'll probably have a better idea of what they're capable of then I will, especially if there is something odd about one part or another which does happen.

 

Going to be 1 3/4 Hooker Long Tubes 3" Collectors, with a 3"-3" Reducer With A Pair Of 3"In/Out Mufflers (havent decided on a pair yet but most likely some Magna Flows or 40 series race flowmasters. Might throw in some cut outs before the mufflers but right now lets just say threw some mufflers. As for the flow #s for the Heads, id have to get them flow benched, guy i bought em off of didn't know.

 

Cam was custom ground to the head specs/intake manifold and 4.88 gears and the 355ci motor. So im guessing they flow decent.

 

Well… educated guess… I’d say 570-620hp, probably in the 6600-7200rpm range. Actually with the 107LSA probably towards the lower/middle end of that.

The headers are too small and putting those 40 series mufflers on it will instantly kill about 50-100hp. FWIW, I’ve never seen any afr 220’s that weren’t done as LT1 heads but that doesn’t really matter. If this thing is going to see anything more then just a run down the track once in a while I hope that those 1.6 rockers are shaft rockers.

The cam just looks wrong to me, in my mind I want less exhaust duration at .050 (maybe less on both lobes, but with about 6* split), an LSA of about 110 and 1-7/8” header primaries, of course, if this is a dyno proven combo what the hell do I know…

I could pop it into DD but am too lazy… what did you get? Remember, one little thing a little off and you can be talking about _a lot_ less HP.

Lets say your car has a race weight of 3700#..., that works out to something that will run about 10.6-10.8 @ 125-130mph. I would gear for about 130-132mph @ 6800-7000 rpm. With a 28” tall rear tire that would mean roughly a 4.35 gear, depending on the axle you choose and how close to the limit you’re willing to run it, that would mean you should be looking at something in the 4.10-4.56 range.

And of course, there is no substitute for running it and finding out what it really likes.

I'd be slightly suprised if that combo built on a 400 block proves to be reliable/durable.

 

I know that flowmasters flow like **** which is why i was gonna add the cut outs. However what is a good flowing muffler then just for my info, might just change it. No not shaft mounted but stud girdles. I agree on the header size however from what i hear those headman (i believe it was) 1 7/8th headers are a bitch to install plus theyre 600 bux. Shell have to do with 1 3/4s right now. *** for the gearing ya i was thinkin in the mid 4.xx range as well. But ya thanks appreciate it.

 

Threw it on desktop dyno, with a 950cfm carb, and large stepped tube race headers puts a peak of 588 horses at 6500rpm and peak torque of 533 at 5500 rpm

With the 950cfm carb and large tube headers w/ open exhaust it puts down a peak of 570 horses @ 6500 rpm and a peak torque of 518 @ 5000rpm

 

My bust on the desktop dyno i left the intake valve test size at like .75" instead of 2.08" and the exhaust at .50" instead of 1.6"

New Best with corrections

Large Tube With Mufflers
573 horses at 6500rpm
525 torque at 5000rpm


Large Tube Open Exhaust
609 horses at 6500rpm
542 torque at 5000rpm


decent no?

 

I like the dynomax ultraflow welded (old race magnums) and the hooker max flow and even the aerochamber. The Magnaflows are a similar design but all the vehicles that we’ve installed them on lately have sounded really wimpy, in some case almost like import sewing machines.

As far as your DD numbers… they’re _right_ in the middle of my estimated range at the low end of the rpm range that I figured. I’d really expect your peak to be in the range that I suggested with appropriate valve train control.

 

What do you think about this set up running on straight 91? I used two dynamic compression ratio calculators. One wanted cam timing abdc + 15 degrees, which is 70, and came up with a dynamic compression ratio of 8.73. The other wanted just cam timing abdc, which is 55, and came up with a dynamic compression ratio of 9.77. For ****s n giggles i put into the calculator what the other one wanted (abdc +15 degrees =70) and it came up with the dynamic compression of 8.73 as well. Which one is right? Are either right? Would help a lot

 

I get 9.75 working it out "by hand"

I suspect that it will run OK on 91 for cruising, maybe with some timing retard... but will be right at the ragged edge with some extra power to be found with better gas

 

Hmm...guess one way to find out. If it doesnt run on 91 ill probably mill the heads to 64ccs bump up compression to 13.2

Think the 11.41 static compression is decent for that size cam? Im starting to think itll bleed off too much cylinder pressure. But ur expertise will move me in teh right direction

 

Man, you’re sorta in that zone where I really don’t like giving advice… Don’t take this the wrong way, but you’ve got a bunch of parts that are radical enough and a combination that is fussy enough that if you half *** one little thing, get the tune wrong… you’ll end up with a mismatched combination that will just be unhappy, and to be honest, if you really knew what you’re getting into well enough to get this running well without a big pile of dumb luck you wouldn’t be asking these questions. I really hope that you’ve got someone that has been there/done that that is going to help you put this thing together/tune it because I’d hate to see this turn into a pile of expensive parts that’s unreliable and much slower then it should be. (and honestly, to some extent I don’t want you thinking “well, that guy didn’t have a clue, this **** doesn’t work at all,” when the real problem is just something that you missed, didn’t discuss, used “because it was there I’ll change it later…”)

That being said, like I’ve hinted, I don’t like those cam specs at all, but if they work with those heads, induction and R/S then, oh well, I might be wrong. That compression with the rest of this combination is roughly what you’d end up with when you are trying to make something that fits under a set of rules and have to deal with things that you normally wouldn’t do. The compression is high enough that you’ll have to be careful tuning but low enough to not really take advantage of the cam, the LSA of the cam is going to cause the power band to spike big in the midrange and kill the top and bottom end, but the big lobes will want to make it rev. Usually an LSA that tight does not make sense to me unless you need to get the power curve all said and done below a specific rpm. I’d like to see more compression and race gas or less and a less radical cam. That cam will bleed off a lot of cylinder pressure at idle, but it will also result in a big BMEP spike in the midrange (say, above about 4000rpm) which I suspect will make the engine detonation prone in that range, and you won’t know without some careful plug reading… I’d be surprised if you’d hear it over everything else that will be happening.

This all reminds me of the engine masters challenge engines, purpose built to get the power band in a relatively narrow and fairly low rpm range and work on specific gas, not what someone would build without the rules constraints. BTW, it looks like one of our regular customers (actually the owner’s brother) bought the willing Kase entry…

 

Taken with a grain of salt, appreciate the help up to this point, wont bother ya again

 

naw man, not a problem with being "bothered," just worried that I'm going to get you in a corner that you're not going to be able to get out of... Ask away, just understand that there is a lot more to this then what could be expressed over a 'net message board.

 

Well, thinking about what you said i decided to give Lunati a call and see what they recommended for my set up.

Came back with damn near the same cam
301/309 advertised
268/276 @.050
.648/.627 lift
106LSA

Ill call the other big ones here later on today, i just dont have time right now.

 

also i forgot to say, i told him what my compression was at (11.41 : 1) and asked him if i bumped it up to 13:1 all other factors remaining the same what cam he would recommend. He told me he would still recommend the same cam.

 

Huh… freaky… I’d love to hear the conversation. Something that you’re telling them is suggesting that you need big duration but need to limit RPM, I’d love to know what it is. The rather restrictive exhaust (for the rest of the combination) that you’re considering using should be pushing them the other way (more LSA…).

 

He asked how much my car weight (gave him an estimate at 3000lbs, cars completely stripped) what i plan on doing with it (1/4 mile passes) What size engine (412 sbc) What compression ratio (11.41:1) What type of cylinder heads (AFR 220s) What rocker ratio (1.6) Size carb (told him 950) Type of intake (Super Victor) Standard or Auto Tranny (standard) How many speeds (5, the tko will be 5 as well) Tire Size (28x10.5x15) All he wanted to know, then i asked him about the rear axle ratio and he said since you have a standard tranny those guys seem to play around with em a lot so i didnt take that into consideration (dont care since i do plan on changing it). Then i asked him if i bumped up compression to 13:1 what type of cam he would recommend and he said the same one. Thats all the conversation was i didnt imply i wanted it to do something special.

 

huh... donno then. Your car is lighter then i expected though...