camdon454

Okay, don't have all specs yet but 468 ci Dyno-ed at 530 hp just over 600lb torque. Turbo 400 with 3200 stall I'm thinking, matched up to a 3:91 posi I found. Hoping to see low 12's on the odd weekend I go to the strip. What slick should I run? I originally thought 29" but I people keep telling me I'd be leaving mph and E.T on the track. Any thoughts?

chadman

We need a little more info to give you a good answer. What is the weight of the car? At what RPM was the 530hp peak?

My initial thought is that a 29" tire with a 3.91 gear is a good starting point given the typical weight and RPM peak of a your typical Olds street/strip car.

I run a 3.73 with a 28" tall tire and go through the traps around 5400-5500 RPM at around 115 MPH which is about ideal for my set up.

wr1970

Year of car? Chassis set up? Chadman is giving you good advice. My 468 went 11.20 at 120 in a 3400 lbs 1967 with boxed control arms air bag 373 full spool. I was using a 29x10.5x15. I also have used a 28x9x15 Not much difference. My 1970 442 has gone 12.50 461ci turbo 400 3600 stall 29x10.5x15 390 posi rear gears. Boxed lower control arms. Full interior street driven car. Both cars are in my album.Just click on wr1970 and it will take you there. Then click all albums.Both cars are operational and still race ready.

rtanner

personaly, on a decent more street than strip car, I default to 28x9, these are roughly the same size as 275-60-15, which allows you to keep the rear of your car low, which is critical for a good launch and high speed manners down track, understand there is world of difference between a street car and a street driven car, check out Pontiac larrys thread on his big olds wagon he is almost in the 11s on motor and dead hooks with 28x9 slicks, ive run 12.20s dead hooking a 72 chevelle hitting a 125hp shot right of the line, factory boxed lowers, factory sway bar, cheap shocks, ride height is critical.

camdon454

Haha, right. Vehicle info may help. As of right now it is a bone stock 70 Cutlass S. My engine was built for me over the winter haven't went to get it yet. 391 rear end will be bolted up in place of stock rear end, no add on as of yet. The motor has no weight reduction other than aluminum intake, iron heads were massaged over. I'm wating on my build sheet for the motor but the hp was made @ 5100..I just want to run it a couple times a year at the strip

chadman

Well with the information you've given I'm estimating your car at around 3800-4000 lbs with driver. With your HP you will likely trap in the 118 mph range. With a 29" tire and a 3.91 gear that comes out to 5332 rpm. In the real world you will get a few hundred rpm of converter slippage so 5500-5600 is a more likely estimate.

I wouldn't go any shorter than a 29" tire if I were you.

camdon454

Thanks for the advice, sure sounds like you know your stuff. I'm really looking forward to it

oldsmobiledave

Best ET will come with a good 60' time. 60' time requires traction. Your best chance at traction is with a big contact patch. Contact patch has two dimensions (width & length). The bigger the tire the bigger the contact patch. Run the tallest & widest tire you can fit under the car & put you thru the traps a few hundred RPM over max hp on your dyno sheet.


With your set up I agree that you want nothing less than a 29" tall slick. I personally run 29.5 x 10.5" under my 72 Olds (actually a 30" tall tire but MT lists it as 29.5" by 10.5"). I am thru the traps at 5900 rpm with 4.10s.


Where did you end up getting your engine built? If I recall correctly you had been talking to Wayne Joss but don't think that you went to him.

coppercutlass

Fwiw im running a 26 in. tall tire. m/t drag radial. 275-50-15 . I was running 3.73 gears just switched to 3.90 . Depending on what i see track time wise i might go to a 275 60 15 drag radial. Although i am running a small block i have seen guys with big blocks running a smaller diameter tire. I do it to try to get more gear out of my set up. I usually drive the street with a 28 in. tall tire.

wr1970

At 530hp 600 ft pounds of torq 391 gears. A smaller tire will not help. Reason copper is he has a lot more hp on tap than your set up. Not to say what you are doing is wrong.What you done is help your combo to get into the proper rpm band to take advantage of the hp you had by moving your rpm band. This guy shouldn't raise his rpm band as he has power on tap with a 468ci.I would be surprised if he doesn't run low 12's to high 11's.JMO

coppercutlass

I have seen lots of fox body mustangs with some serious power on 26 in. tall slicks running in the 9's Thats why i said for what its work (fwiw) . A tire is part of the tuning procedure .

Edit: i may add im not telling him to run a shorter tire buy im just sharing my experience on why i went with a shorter tire. Atleast throwing that out there.

wr1970

Oh i don't disagree i have seen the same thing when it comes to mustangs and vega's. 530hp at 5100 rpm is very good my guess is his peak may be 5400/ 5600.If it was me that would be my shift point and see if it would cross the line at 6000 or just under.If it does it would be the perfect match. He shouldn't see rpms above 6000 unless he has taken measures to hold the bottom end from coming out the bottom.

coppercutlass

I was just putting that out there. By the rough calculations chadman did he should be using a 29 in tall tire but it can still vary. The diffrence between a 26 in. tall tire and a 29 in. tall tire is 400 rpm. Another thing to consider is shift points. That will also change things.

TripDeuces

"Run the tallest & widest tire you can fit under the car"

What Oldsmobiledave said.

camdon454

Sounds like widest and tallest it is. Great info guys, seriously. I have grown up at the strip but never had a car of my own to run yet. This is something I have always wanted to do, but not until I could afford not to "half *** it". I'm happy with my build so far, suspension will follow over the next winter. And Dave, I didn't go with Wayne but not because of my conversations with him, just found a way to make it easier for me here in B.C.

oldsmobiledave

Can we expect to see you at the season opener in Medicine Hat?


Post some pictures of your car.

camdon454

Haha!! Maybe Medicine Hat next year for the opener. I still have to wait a month to even get my car out of storage, still snowed in where I store it. I'm hoping for the July race in Spokane Washington to pop the cherry. I'll try again to post pictures, I thought I updated my profile but it didn't work apparently.

GEARMAN69

Actually I am running 26x10 slicks on the wagon with 3.08 gear but have hooked hard with 1.69 60 foot but the wagon weight over the rear gives me an advantage there. GM A body cars with level ride height can really do well on small tires. The 29 w 3.91 would be good if you have a 5500-6000 shift point also beware the axle splines if still running 28 hope not. That is not likely to last with a 29 and that engine. had a S10 that weighed only 2850# with an 4.10 8.5 rear and bolt in 28 spline axles. With a 11:1 406 SBC (est 465 ft. lb) it regularly did 1.59 and a 1.57 60 ft on 28x10 and later 29x10 slicks and I found those axles ends twisted later and that was in a light vehicle and medium cubic inch.

80 Rocket

While I agree with what you are saying to an extent......the title is "best slick size for ET". The widest tire you can fit will not net the best ET. I see a lot of cars with tires that are just overkill. Hell, my dragster has tiny tires compared to all the others. I run 33x12s, all other rails I see are at least 15" wide. I have been 1.16 60ft with the rail and went 8.48 @ 155mph.


Also, look at comp eliminator class. Those guys run the smallest tire that they can get to hook, and they are pretty damn small. More tire = more rotating mass = slower 60ft = slower overall ET.


I run a 30x9 Hoosier radial slick on my 80 Cutlass and have been 1.49 60ft on them footbraking. We run the same tire on Milan's 69 Olds. that has been a best of 1.26 60 ft and 9.34 @ 144mph.

GEARMAN69

^^ exactly 9" is always enough ask any woman ,

wr1970

Don let's clear up one thing please. I am not disagreeing with your post above. A 69 will not work well with a 10.5 correct! Isn't that why a 9 inch is used. That has been my understanding. Now as for a 70 can run 10.5 no problem. I can see where a hoosier 9inch may be better less side wall flex has a lot to do with that. I have been 1.50 foot brake on 10.5 mickey's. I found that 14/15 pounds work better when using a 10.5 mickey slick on my combo. I have a pair of 28x9x15 mickey's but can't use them on my 67 but may try them on my 70 again with my 468. I have never tried this as this 468 is out of the 67. I will probably try both 10.5 and 9 inch to see which works best.This is a different 468 is a different combo than my 461 used for years.

80 Rocket

I do not believe a 10.5 will work in a 69 without modifications. However, the car has absolutely zero need for anything bigger.


Here is something to consider......you have a regular 2wd pickup truck and a 2wd dually pickup truck. Which one will be more likely to get stuck in snow?

wr1970

LOL i hear you. But we are not talking snow. Mylan's car has been built for optimum performance with parts used. That is something some don't have.The et his car runs drives the point home. Thanks for the reply Don.

oldsmobiledave

Who would be stupid enough to buy a 2wd dually? Forget snow I have seen them stuck on wet grass.

80 Rocket

Hahahaha! See my point?






ps- I used to have a 2wd dually

rtanner

Also, look at comp eliminator class. Those guys run the smallest tire that they can get to hook, and they are pretty damn small. More tire = more rotating mass = slower 60ft = slower overall ET.


ok 80 rocket, this is exactly the kind of information, that fast guys don't share with others

rtanner

Lol!!!!

80 Rocket

Did I forget to mention reading that information is $50 per person?

GEARMAN69

Man I wish I had video recorded this fast little 66-67 Chevy II at Cedar Creek that was just drilling those tiny 26x8.5 slicks and it was quick as hell off the line twisting the rim to the ground

rtanner

that is a buddys car from Corsicana, he is running 6.90 1/8th, 26x8.5, he has taken a lot money with that car

young olds

I can get a pair of Goodyear 29x10 for a good price but curious what you guys thought about the compatibility with my car. 66 f85, 355, manual trans, 4.10 gears. They come with 8" wheels, 5" backspace and was able to test fit before purchase.
7C658298-001A-44BB-84B7-5BBD95C0B876_zpsreqkykou.jpg

wr1970

I think 66/67 about the same on wheel well. 29x10 should fit. I would go 30x9 in mine but no room with out modifying wheel well.

young olds

It fits, like I said I was able to test fit before I purchase. Wondering if it'll be a good size for my car/combo before I buy.

69442w30

I'm running a 69 w30 3800 ibs 468 with th 400 3,000 stall with 4:11 stock wheel wells no tubs I can fit a m/h racemaster street slick 28 tall should pull mid 11s in the 130 m ph range at 6 grand

oldsmobiledave

Cars running mid 11s don't go 130 mph.
Your math is wrong somewhere or there is a typo in your ET or mph.

young olds

Couldnt he if he spins and gets bad 60's and it just runs hard out the top end? But I do agree that is fast for mid 11's

oldsmobiledave

No. 11.5 is 115 to 118 mph. No way 130. That is 10.50 and faster mph

80 Rocket

If he spins bad, yes, 130mph running mid 11s is possible. I see it all the time with hopped up newer cars at the dragstrip that don't hook worth a damn because their tires and chassis are inadequate for the power laid to the pavement.


A few years ago, just for grins, I took my dragster down the track on a Tuesday night track which had no prep (or, I should say the street tires that went down the track killed any prep that was laid). I went 10.03 @ 144mph all out. The guy in the tower commented how it looked like old time drag racing when cars/dragsters lit up the tires off the starting line and did 100ft burnouts off the line. This dragster is one in which ran mid 8s @ 150+mph normally on a good track.


However, 69442w30 might think his car will go 130mph while hooking up. That combination would be well into the 10s and knocking on the door of 9s if the chassis/tire combination is working. To run mid 11s @ 130mph means you have serious HP and serious traction issues. To go 130+ in the 1/4 mile at 3800lbs race weight requires 700+ hp.......probably more like 750hp.

oldsmobiledave

Obviously I was talking about the combination that he posted. Not a dragster and not a later model modern super car.

wr1970

How do you compare a dragster to a heavy door car?How do you compare a modern super car with computer traction control and efi systems computer control to a old school heavy car? Apple to a orange?