Noob questions

Just placed my order today with Hillbank. Based on what i read here and an experience with cable shift,doing a RHD Mk1.

Have been tracking a Lotus elise for the past two years, single seaters before that. The Lotus goes to the track on atrailer, but I also street drive the car on smooth roads.

The GT40 is primarily for trackdays will also prob move from track to track on a trailer so I can have good ride height, wheels tires jack brakes etc on hand.

Would love advice on motor choices. I see many if not most have apounched out 351/427 combo. Is this a good motor for the track or is it overkill?

I have looked at 302 based motors. It seems the choices these dyas are a 331 or 347 with same crank as 331 but bigger bore, or the motor du jour of a 363. It seems pretty much every hyd lifter mtor is limited to 6500 rpm, wherasa sold lifter can go to 7500. For the track is 6500 a limitation, is it better to go with a higher redline. Does anyone have experience with a 363, it it a fast spinner or a rough engine. It seems that a good 363 motor even with hydraulic lifters is 520-540 hp and 480 ft lbs on pump gas. A big bore 347 with short 3.25 crank is perhaps 20-40 hp less. Does it reall matter in a car so light.

Alternatively is it wortwhile going for a high rev race motor?

Is it even worth going with a 302 based mtor or should one just do the 427W.

Thoughts on carb Vs injection? and suggestions on engine builders.
I have looked atr Keith craft, Gordon levey and Benett racing so far.

Since it takes SPF almost a year these days i still have lots of time to figure it all out, but would greatly appreciate opinions from those experienced.

car will do 80% track and maybe 20% street.
 
Lots of excellent questions. I'll offer some thoughts, with the strong caveat that I am a would-be owner myself. The experiences of those who currently own and drive these cars are obviously more valuable, but I would hope to at least provide some thoughts for discussion among that set.

Is a 427 stroker a 'good' motor for a GT40? Well, of course, that depends on what you intend to do with it. It is certainly more than any GT40 really needs. There are several owners here who have such combos, who rarely, if ever, actually use their cars. Jack Houpe is especially candid when he admits that if he had it to do all over again, he would make an alternative engine choice with substantially less power, as his exceptionally well-built 427 Windsor simply overpowers the car and makes it less pleasant to drive. I went for a ride with him in Arkansas a few years ago and found it (from the passenger seat) rather frightening, as the car would (and did) quickly snap out of control with a bit of injudicious throttle-prodding in second gear.

Having said that, he subsequently let me drive it (he's a very kind man indeed!), and acceleration in the higher gears was a religious experience!

Besides the issue of originality, 302-based motors have several advantages, including smaller size (marginally) and lighter weight. Max RPM is inversely proportional to stroke (displacement). A 302 will zing to high rpm but will have less torque potential, while a 363 (363? Really?) will be the opposite.

347s are good street motors but are generally considered too big for track work; presumably a 363 would be even worse. A friend of mine has a beautiful piece of modern art, in the form of a well-built 347 (with forged crank) with a block split cleanly in two that he blew up on the front straight at Thunderhill Raceway.

The 331 seems to be the best compromise between additional power and rev-ability, and low-end torque. I opted for a Scat forged crank 331 stroker for my GT350 clone.

The advantage to a stroker is that you can develop more power/torque at a given rpm, or put another way, you can achieve a given amount of power/torque at a lower rpm. High rpm is extremely hard on valvetrain components and also contributes to greatly elevated oil temperatures. There is a huge difference between 6500 and 7500 rpm.

My friend the art collector is a bit of an infant on the track, in that he likes to rev engines to the moon rather than simply upshifting, so he is likely responsible for his engine's demise. If he had established a lower redline, he might have been as fast (or faster) and his engine might still be in his Mustang instead of his art collection.

High-rev race motors are sexy and expensive, and also maintenance-intensive. Figure on checking (if not changing) valve springs once or twice a season, depending on how often you use it and how aggressive you are with it. You also need to pay much more attention to oil temperature management.

I have a 540 horsepower 408 stroker (about as big as you can safely go) 351 Cleveland in my Pantera. It's shockingly fast on the track, with a self-imposed 6000 rpm redline. So I'm not fundamentally opposed to strokers built towards the bigger end of the spectrum, as long as their limitations are respected. But I wouldn't put an engine that big in a GT40, which weighs almost 1000 pounds less.

Carb is simple and inexpensive. Injection is complicated and expensive. Both will deliver similar performance. Assuming it's set up correctly (which is definitely not a foregone conclusion), an injected motor is easy to live with, in that you just turn the key and it starts and runs perfectly. But getting to that point can be a frustrating and expensive experience, and in extreme cases, you might blow up an engine or two along the way (as some other people here can personally, and painfully attest). Carbs are crude but effective, and it's fairly simple to set them up on the safe side, then advance towards incremental gains in performance through tuning.

Webers are their own brand of expensive and complicated. Traditional Webers won't flow enough to feed a big engine (which is why the big-block GT40s all ran Holleys, either one or two four-barrels). They are 'correct' for a 302-based engine, but require tuning knowledge and experience, and can prove enormously frustrating. Once set up properly, they are reportedly very rewarding and enjoyable. But I would characterize cars like that as very much the exception rather than the rule. Most Weber-induction cars I've seen have huge caveats attached to them, i.e. "It runs FANTASTIC (above 3000 rpm)" or something like that.

You will probably get a lot of opinions, some contrary to mine and some in agreement. Take them all in, mull the question over and that will enable you to make the decision that's right for you.

I would put forth the proposition that the Pathfinder setup (Mk 1, RHD, rod shift, 302 with Webers) seems to make people very happy indeed, as a dedicated track car, and given your description of your intended use, that is probably a good example to emulate.

I would also suggest NOT putting a roll cage in the car if you ever want to drive it on the street (or rather, if you want to drive it without wearing a helmet). Roll cages are lifesavers in track cars, but have proven to be absolutely deadly in street cars to unhelmeted occupants.

Good luck, and please let us know what your ultimate decision is!
 

Mike

Lifetime Supporter
What tires was Jack running? I don't find mine with the 427 to be that difficult to handle. My Ford GT with a pulley and tune was more of a handful on cold Goodyears with all the low end torque. I don't track mine so maybe my opinion would change if I did. Might be water under the bridge now not sure but you might consider having Olthoff do the install and be able to take advantage of his vast experience racing and setting up these cars.
 
I do track days with my Roush 427SR. Love the wide torque band and kick in the pants you get coming out of corners. If I were doing it over (and cost was not a factor) I would get a Keith Craft 8 stack injected 427. I've worked on the jetting with an A/F meter, but still get rich readings in corners. Injection would respond quicker too. You're going to have to do this at a minimum:
1. Harder brake pads.
2. Stiffer springs
3. Adjustable shocks.
4. TRACK TIRES such as Hoosier R8's or Nitto NT1's. Car will wallow and be unresponsive with street tires.
5. Accusump or better yet dry sump. Dry sump will take some customization by engine builder to accommodate with A/C.
I also have a Lotus Europa (Zetec) that I do track days with. You will find the 40 does not approach the nimble handling or braking of the Lotus, but the kick in the pants out of corners is a blast. With your level of experience a 427 will not overpower the car.
 
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Dave Hood

Lifetime Supporter
Congratulations on placing your order!

I also recommend having Dennis do your set-up. I also like the Eight Stack injection system he uses. Dennis has developed his own ECU for it as well. Dennis would also be a great resource for input on your engine choice. He's worked with more GT40s than anyone in the US, so I'd include his opinion before you make a final decision.
 

Rick Muck- Mark IV

GT40s Sponsor
Supporter
As a Supeformance dealer I will reinforce the value in having the car delivered via Olthoff for completion.

NO one has more on track experience in an SPF GT40 than Dennis and no one has completed more GTs than his crew.

If you really are looking at 80% track time in the car there are several track upgrades that Olthoff can provide. I would recommend you contact him and review the chassis you ordered so any changes can be accomodated (although you are 10-12 months out on build) rather than requiring them to be done here.

The phone call to Dennis will be your second best investment.................
 
Thanks for all the great advice. yes Dennis will be doing the build. I visited him 2 years ago(keeping the dream alive) and his talent was clear to see.

Had not yet really thought about the tires. Some seem to run some type of racing avon.

Hoosiers sound like a great plan, already run pure Yoko slicks ont he Lotus.
What wheels do you need to accomodate the hoosiers?

How are the brakes. Currently I use pagid RS14's and motul fluid, love that combo. But are the discks up to serious heat, or is that something to change too?

Had thought about a 302 based Motor because Dennis had told me that with a carbed 302 type block you can HSR vintage race, which may have some appeal in the future.

I do love the dry stack look though. If I went 351 based woudl probably do an aluminum block, coming from a lotus lightness is next to godlyness. My concern is that a 427 is just too much go to really control on a track so you just bast down the straights and then Gingerly got hrough the bends.

Dry sump is a must.

Please keep the suggestions flowign theya re really valued.

I think the motor choices are a high rev 331, a 347 with the short 331 crank getting to 347, a 363 which has the long stroke 347 crank with the big bore 347 pistones. so somewhere from 460-520 hp and over 400 lbs of torque depending on One can alkso do soild lifters to really run the motor up the rev range. Or just do a 427 combo.
 

Dave Hood

Lifetime Supporter
Avon street tires run a bit more than $2,000 a set. Dennis uses Hoosiers on his MkII track car and could let you know what wheels work with Hoosiers.
 

Rick Muck- Mark IV

GT40s Sponsor
Supporter
Which tail configuration are you doing? The "wide" tail requires either the supplied wheels be widened or other wheels be purchased. The "standard" tail comes with 10.5" rears which work well with the Avon CZ66R tires in 295/50x15. For pure track tires there are numerous tire options from slick to treaded vintage types.
 
Stock discs should be OK. Ask Olthoff about pads. I think he has a Performance Friction one he prefers.
For wheels Othoff probably uses 15" for vintage rules. If you're not constrained by rules look at 17" wheels for track use. Gives you a wider choice of tires.
 
Which tail configuration are you doing? The "wide" tail requires either the supplied wheels be widened or other wheels be purchased. The "standard" tail comes with 10.5" rears which work well with the Avon CZ66R tires in 295/50x15. For pure track tires there are numerous tire options from slick to treaded vintage types.
As I undertand it there is a narrow body(which was the original pre 67) then the standard SPF which is wider and the wide body. I hear there are numerous limitations to the wide body in terms of wheels tires and trailers.

Currently have the standard spf body which I suppose is mid wide and the single hole front.

Are there serious real advantages to the wide body?

As to the 15 in wheels are good/great track tires available, or do you need to get 17 in rims for the slicks. In any event prior experience dictates at least two sets of rims. One would be for street/wet tires and another for a slick track type tires for dry track days. Does this mean getting std 15 in rims and another in 17s or are there really good track tires for the 15 in rims.

Currently I run Yoko full slicks on my lotus and love them not least because they have very limited lateral sidewall flex which makes I think for better steering and a more controlable break even if the limits are much higher. I tried R compounds before and they were ok with lower limits but really did not last long, loosing grip after a few cycles. With the Yoks I can go about 4 days or 16 20 min sessions by which time the left rear is shot and the others look Ok but are heat cycled out.

While I know all cars are different, On street cars like my m3 and another I love PS2's but they are not that grippy for the track and will chunk and melt with hard use. On the lotus there are yoko 008's for the street which are imho dangerous on track, but their limits are low enough for the street and they are comfortable. The adav slicks on the Lotus though are great. Some friends run hoosiers which have slightly lower limits but are pretty great too.

So is a wide body a must? are there great track tires in 15 in sizes or must one go to a 17. D0nt love the 17 look on a Gt40.

How far can one go in terms of brakes, are there adjustable shocks or is the stock setup pretty good.
 

Rick Muck- Mark IV

GT40s Sponsor
Supporter
The stock brakes with the right pads will do all you need short of serious endurance racing. They are the equal of what the Gulf cars ran.

The "wide" tail does have some drawbacks....tough to trailer and tires/wheels for the street are an issue. Also rear vision and backing up are challenging.

If you want optimum performance with s DOT tire then 17 or 18 inchers are the answer. To me it just doesn't LOOK like a GT40 without 15' wheels and rubber. The "mid-tail" which is the standard SPF GT40 deck is the most popular setup and short of all out total track performance will give you all the tire needed for an "E" ticket ride.
 
The stock brakes with the right pads will do all you need short of serious endurance racing. They are the equal of what the Gulf cars ran.

The "wide" tail does have some drawbacks....tough to trailer and tires/wheels for the street are an issue. Also rear vision and backing up are challenging.

If you want optimum performance with s DOT tire then 17 or 18 inchers are the answer. To me it just doesn't LOOK like a GT40 without 15' wheels and rubber. The "mid-tail" which is the standard SPF GT40 deck is the most popular setup and short of all out total track performance will give you all the tire needed for an "E" ticket ride.

I think for the street the 15s will be more than fine, realisticaly you can only corner so hard and go so fast on the street, plus still have the lotus and one or two others for the street maximus. I think given the low mileage these cars do, and my expected 30% street use any stret tire is going to become hard and brittle before its worn.

Not looking for a Dot tire for the track so its really a question as to whether there are great 15 in track tires. Will ask Dennis this. Meanwile its great to hear from people with actual experience, please keep the suggestions and experiences flowing.

Currently leaning towards a bored out short stroke 302 block that can rev, maybe even in aluminum. A 302 based motor will still make 500+hp and is 100lbs lighter than a 351 based motor, aluminum is 100 lbs less than that. 180-200lbs is the weight of a passenger. Maybe you lose a bit in low down accleration but braking and cornering will be significantly improved. I think the rule of thumb is that 10lbs equals 1hp. Still want to have OMG speed , but maybe one can also overpower the car in which case you will be tiptoing around the track. Will discus with Dennis and see.

Happy to hear the brakes are good. From my experience most cars have decent calipers so a good track pad and high temp fluid can work wonders providing the disks them selvs are then are up to the temps involved.

The big change from the 60s is aero and brakes. In a modern driving enviorment you can gain a huge amount by trail braking far later, this requires great brakes that can last with good modulation. Aero ruins the lines of the car though and unless you have areal big wing and splitter do little till over 140ish which is an unlikely speed for any bend anyway unless youa re iun something like a single seater or a radical.
 

Steve

Supporter
Sean,

Just a heads up: if you ever decide to vintage race you can only use a non-stroked 302 with an iron block. You can use aluminum heads, but not an aluminum block. You can bore but not stroke. Dennis will confirm this too. You're right that a 302 based block will make plenty of power. You might need to rev it more but Dennis is getting 580hp out of his 302 (at least). If you're going to rev to 7500 though you should consider shaft rockers and titanium valves. Either way, dry sump is a must.
 
I do track days with my Roush 427SR. Love the wide torque band and kick in the pants you get coming out of corners. If I were doing it over (and cost was not a factor) I would get a Keith Craft 8 stack injected 427. I've worked on the jetting with an A/F meter, but still get rich readings in corners. Injection would respond quicker too. You're going to have to do this at a minimum:
1. Harder brake pads.
2. Stiffer springs
3. Adjustable shocks.
4. TRACK TIRES such as Hoosier R8's or Nitto NT1's. Car will wallow and be unresponsive with street tires.
5. Accusump or better yet dry sump. Dry sump will take some customization by engine builder to accommodate with A/C.
I also have a Lotus Europa (Zetec) that I do track days with. You will find the 40 does not approach the nimble handling or braking of the Lotus, but the kick in the pants out of corners is a blast. With your level of experience a 427 will not overpower the car.
What type of pads?
Are there adjustable shocks for these cars? who makes them.
What type of wheels do you need to run hoosiers.
Def doing adrysump no matter what.

Interesting from a lotus driver that the 427 is not too much. I guess its the natiure of the GT40. My fear is the torque of the Gt40 will unhinge the rear coming out of bends, I supppose that is a tire thing as much as anything.
 

Rick Muck- Mark IV

GT40s Sponsor
Supporter
Given that you're looking for a track car, did consider the GT40R version from Pathfinder?
The Superformance GT40R is sold as a "race car" only and street use is not advised. The concerns are the roll cage and proximity to your head without a helmet. There was a thread here years ago with someone who lost a friend that was street driving a roll caged car with out a helmet and a collision caused head injuries that were fatal.

The "R" is available from any Superformance dealer as an order. We can do a "street" roll bar setup that does not intrude on the cockpit and therefor poses no head injury potential.
 
RJB and others are right. $ for $ the Pathfinder GT40R is hard to beat for price and performance. I believe CAV also does a race version GT 40 that is campaigned in South Africa quite succesfully. Not sure if they are available here in the US however. Both are certainly worth a look.
 
The Superformance GT40R is sold as a "race car" only and street use is not advised. The concerns are the roll cage and proximity to your head without a helmet. There was a thread here years ago with someone who lost a friend that was street driving a roll caged car with out a helmet and a collision caused head injuries that were fatal.

The "R" is available from any Superformance dealer as an order. We can do a "street" roll bar setup that does not intrude on the cockpit and therefor poses no head injury potential.
Understand about the roll cage & "race car only" nature of the R -- but I was under the impression that the OP wanted exactly that and was planning on trailering the car to track days.
 
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