Gear suggestions plz

[351wStang]

I emailed Summit to ask them about what gear ratio they would suggest for my car. This is the first serious race car i have built that was actually mine. They suggested 4.89's, with a 31" tall tire. The closest thing i have seen was 4.88's. Im working on a stroked 351w (393). Victor Jr. intake, fully ported cast heads (planning on valves around 2.20 - 1.75). 750cfm or 850cfm Speed Demon, need to do more research to make up my mind. Eagle crank 3.85" stroke, eagle rods 5.9", possibly ROSS pistons (welcome any suggestions there, forged of course). Looking to get around 11.50:1 with 60 cc heads. Still undecided on my cam. Hydro roller because i will attempt to drive this car on the street a couple times a week. The reason for such large valves is big runners and 1 cam suggestion i have was around .588-.612, dont remember duration or lobe sep. Not a vacuum friendly cam. I know this isnt very streetable, specially with a 3500-7500 rpm range and a c-4 trans with a stage III shift kit. My goal is 500+whp 550+ would be great, and around 10.90's in the quarter. I expect to be building this car for a couple years though. If my plans work out then traction will not be much of an issue. Also while i have described my project just how much of a roll cage do you seem to think i will need? I was thinking maybe somewhere along the lines of 8 point. I wrote all this to try to help explain my situation and in hopes of an agreement to the 4.89's or similair.

[HiFlow5 0]

4.88's is a damn steep gear. I hope you can get the traction to make the car hook with those gears. I think 4.11's would be a decent all around gear. They might help out better with the C4 by the end of the 1/4 mile, because with 4.88's you might be taching out.

[351wStang]

I want to be pushing around 7,000 rpms when i cross the line. This motor will make most of its power at about 6,700 rpms. I think anyway. I think between tires, lift bars, some launching practice, and one helluva burnout i should be able to hook up. Im planning on launching right at 3,500 rpms, maybe a little more.

[SkylineUSA]

With a 31" tire, 4.88, and that much torque, all I can say is WOW!

I would lean towards 4.56 range myself.

I think the 4.11s with 31s would not leave you in your sweet spot. I am being lazy to actually run the numbers, because I am a

Good Luck on the car.

[boosted331]

With 4.56's and a 31" tire you'll be able to go 140 MPH @ 7000.

Might want to rethink the 2.25/1.88 valves, those are big block sized and are way, way, way too big for a 4.03" bore.

[351wStang]

I had the chance to do a little more research this weekend and got to stop by a few machine shops. Withj the money I would have involved in porting and valves, springs, ect. I may get the victor jr heads for nearly the same $ and be done with it. I would be leaving the 2.05/1.60 valves that come in them then. Im just now getting the motor and everything and still saving money so I have plenty of time to make up my mind.

[SkylineUSA]

There 2.05s? Those should be a lot better suited for the engine you want to build.

[chevytrucks92]

Originally Posted by boosted331

With 4.56's and a 31" tire you'll be able to go 140 MPH @ 7000.

Might want to rethink the 2.25/1.88 valves, those are big block sized and are way, way, way too big for a 4.03" bore.

I was thinking the same thing about the valve size.

And if that car will make 550 rwhp, unless it just flat out weighs alot, it's gonna be much faster then high 10s in the 1/4.

[351wStang]

Car weighs about 2500lbs. Lx trunk car, 4cyl.

[chevytrucks92]

Originally Posted by 351wStang

Car weighs about 2500lbs. Lx trunk car, 4cyl.

well if it will make 550 hp at the back tires then its gonna do alot better then high 10s!! But you might as well plan on shelling out the $$$$ if you plan on making a 351 do that! (ex: this winter we spent $2400 on just the bottom end+valve job and valve springs(probably $400) for a 406 small block Chevy, and that is not even counting the cam, becuase it was still good and the shop that did ours estimated it to have 550-600 hp at the flywheel)

[351wStang]

I expect to have around $9500 in the total project over the course of a year or two. I will be living at home with very little expenses so I can save a good bit of money. I will also be building the engine and trans myself, along with all the suspension mods. The only work I will pay someone else to do will be machine work on the block.

[ridge_runner]

yea i say go with the 4.11s atleast for now

[ridge_runner]

im plannin on droppin some 4.11s in my bronco

[351wStang]

4.11s wont put me in my power range across the line.

[duplox]

Those valves are pretty large for the inline valve setup, 2.25int/1.76exh is pretty much the biggest you can fit in a canted cleveland head.. I'd say around 2.15/1.65 would be a good max for inline.
If you do the porting yourself, you can save a lot of $$. But nothing replaces alloy...
With 500hp @ the rear wheels and a wet vehicle weight of 2675, you should be running around a 10.2 in the 1/4. 550, you should be around 9.9.
I'd reconsider using a hydro cam in your motor; 7500rpm is pushin it. Lifter pump-up might be a problem. I'd rather go with a solid flat tappet.
As for gear, I'd go with 4.56. A 10 second 1/4 is around 135-140mph across the line. As boosted331 said, 4.56s will get you around 140mph. If you want to mess around with MPH/gears, heres a nice calculator:
http://www.onlineconversion.com/bigger_tires.htm
good luck, sounds like a good project!