Arizona Mike

I'm looking to put a 2001-2002 F-body drivetrain in a '65 AC Cobra replica (LS1&T56). Rear is a Ford 8.8" with 3.73 gears and Torsen. Rear tires will be 315/35-17, which is the same diameter as stock Z28 rears, so this is just like a 3.73 in your cars. The cars tend to be rear heavy, but probably can't put much more than 400 ft-lb to the road in 2nd gear. I may add a 150 wet shot later for third and 4th for 1/4 mi runs.

I'm looking for an inexpensive but reliable 400 FWHP (320 RWHP) with anything more just gravy if it comes without spending much more (like cam choice). I want a 6,800 RPM limit with a planned 6,500 shift point.

The headers will be custom built 4-into-4's that mate with the kit's 4-into-1 collector side pipes. It will essentially be a very long unequal length design, probably 1 3/4" I'll probably start with the "stock" glasspacks and upgrade to 3.5" chambered sticks later.

This car runs about 2,200-2300 lbs with a Ford 5.0 and T-5, the LS-1 being a bit lighter but the T-56 is about 50-60lb heavier than the T-5 so it'll be a wash but with better weight distribution. The 2002 Z28 is almost 3600 lb by comparison, so this car will be more than a third lighter.

I want something that will cruise on the highway at 1600-1700 without bucking, but I don't mind if it lugs some (I can downshift to accelerate quickly). I want to maximize torque between 4000 and 6000 rpm.

I'm thinking of stock LS6 intake, stock heads, cams to match the engine to the car weight and rear drive ratio, a ported stock TB with an adjustable stop, and a Stock MAF. Springs, lifters, and chain will probably be changed out with the cam, probably keep stock rockers if the cam allows it. A dyno tune goes without saying.

I'm looking for cam and spring recomendations good for such a light car and high RPM but conservative enough that I don't have to worry about clearing the stock pistons. The cam should be nitrous friendly since I may go that route later.

Thanks,

Mike

PS: being a light (and open car), there will be no AC or PS.

zracer28

iTrader: (1)

tr224 sounds like a good choice here...a mild cam but has proven results with a good tune and it should net you way more than 320 rwhp with the right bolt ons. Just read through the thousands of cam threads on here and you should get a good idea to meet your power goals

Mike94ZLT1

iTrader: (3)

2nd vote for the TR224

calongo_SS

iTrader: (7)

I'd talk to the guys at texas speed about the Torquer R2 cam. TR224 is just to small for a car like this. The torquer is a 232/234 .595 or something like that. It will easily clear the pistons, will drive nearly as well as the 224 and make more power. For a really light vehicle you don't need the low end grunt of a cam like the 224. You could go even bigger, I have a 233/239 from TSP and it has plenty of low end in a much heavier vehicle, and it really likes the juice as well.
BTW, you could probably get your 320 rwhp with the stock cam.....

Arizona Mike

I should add that I don't need smog (replicas are registered as body year (1965) in Arizona -- I hope this does not change).

I'll check out Texas Speed. I was looking at Thunder racing and wondering if the 224/227/.563/.563 114 nitrous/blower cam would also be a better choice than the 224/224/.563/.563/112.

Mike

s346k

iTrader: (4)

i would suggest lgmotorsports g5x3 on a 114 cam.

you obviously don't need much tq down low to get that thing moving, nor do you need a massive cam. the x3 with a proper tune will give you excellent street manners and also pull very hard up top. you might try to check out some dynos of this cam either at www.lgmotorsports.com or this website. the x3 is a tad smaller than the ms3 (237/242 113 lsa) but can be had on any lsa, i suggest 114. compare the power curves of the ms3 and g5x3, i think the x3 will make you happy.

Arizona Mike

Thanks for the inputs guys, I've been looking at the "cam only" sticky in the Dyno section and understand that I can get a lot more than I need with a ported TB, TB bypass, and cam. I've been listening to sound files of the g5x3 and ms3 out of duals and almost wet my pants!

Mike

99blancoSS

iTrader: (115)

2200 pounds?!? trex all the way, you dont need torque here just gobs and gobs of HP!

Bombguy99z28

Do you want a drag race car? Honestly, that car will haul ***** with a stock LS1 in it, let alone a modified one. Heck a stock LS1/4l60 (with gears and stall) in an rx7 (2700lbs) does 7.5@91 in the 8th (mid 11s 1/4), so with a 2200lb chassis and a stock LS1/6speed you'd probably see mid-deep 11s @ insanely huge mph.

I'd honestly look for a cam that doesn't give you as much torque down low but gives more power up top (G5X4/similar cams) because you won't need as much torque to get going and it'll pull like a rocketship once you do get going.

I'll tell you straight up though, if you do that and slap a 150shot and tire on it, you'll prolly need some wheelie bars if it hooks.

JakeFusion

iTrader: (7)

I agree. I think you'll want a high RPM cam. MS3, G5X3, G5X4, T-Rex, or anything over mid 230s intake duration will be a great match.

strokedls1

iTrader: (1)

I would go for a futural f13. My buddy has one and it is easy to tune and very mild. Low 230 duration.

Arizona Mike

Thanks for the replies. Like I said I'm looking for gains at 4000+ RPM. Based on what I've seen in the Dyno area I might never do the nitrous. I probably don't need to plan the cam for nitrous anyway since most of these big cams are traditional splits.

Bombguy, I do not want to ruin the street mannors, just take advantage of the fact that a cam that might be barely streetable for 3.46:1 3,600lb might be pretty reasonable for 3.73:1 2,300lb.

Mike

james562

iTrader: (35)

MS3 all the way... call Jason at TSP he should be able to point you in the right direction

s346k

iTrader: (4)

i think the next question is this: how high do you want to spin that motor?

if 7k+ shift points don't scare you, get the t-rex, it is a f'n animal.

if you want lower shift points with similar (slightly less) power, choose a g5x4 or ms3...

Arizona Mike

s346k, I'm going to do some peak piston velocity calculations when I get home from work, but with the relatively short rod ratio of of the LS1 (1.684) i'd probably not be willing to go over 7,000.

I'm only willing to to springs, retainers, rod bolts, possibly pushrods and seats.

Mike

mr2guru

iTrader: (16)

Do a TRex.... with 2200lbs you don't need much low end to be perfectly driveable.

DaleMX

iTrader: (4)

I'm running a TR230 in my Datsun 280Z. There is so much torque at the low end that it will really suprise you. I run my idle at 825 and it has a nice lope to it. To keep the engine from stalling when the Taurus fan comes on I programed the idle up to 900 1 degree off of the fan setpoint.

That car would be so scarry that hitting 6800 would be a rare event anyway. Mine pulls so hard past 3000 in 3rd gear that traction goes away and white smoke and black stripes appear in the rearview mirror . Maybe the 195/70 14's could be the problem there!

DaleMX

iTrader: (4)

Oh yea, the rearend is a 3.54 and the weight is around 2800.

Arizona Mike

Looking at average piston speed, we can go well over 7,000 RPM with stock forged pistons.
I'm more concerned with max piston acceleration/ring flutter. The general rule of thumb is 100k ft/s^2 maxiumum acceleration. With the relatively low rod ratio of the stock 346, this works out to be 6,800 RPM (so shift near 6,500-6,600). I don't want to go higher and will probably upgrade my rod bolts anyway. I'm sure some here feel this is to conservative . . .

Mike

RPM..........Acceleration (ft/s^2)
6500........90.7k
6600........93.5k
6700........96.3k
6800........99.2k
6900........102.2k
7000........105.2k
7100........108.2k
7200........111.2k
7300........114.4k
7400........117.5k
7500........120.7k

DavidNJ

Unless you go to a solid lifter cam, you don't have to worry about anything 'over 7000'.

Your headers won't be as good as normal LSx fare, giving up quite a few ponies over a modified LSx. With headers and LS1 heads, few are over 400rwhp. And again, your headers won't be as good.

You would probably find something in the 224/224-228 range a good compromise. It is mild in this forum, but most here don't have cruising at 1600-1700 as a goal. I didn't think most Cobra owners did either.

Question: Does your state doesn't have emissions issues? In NJ, you'd have to have all the emissions appropriate for the year of the engine. So that would have to include cats and probably the stock exhaust.

Question 2: What chassis are you using?

P.S.
Excellent engine choice for a Cobra.