A good engine question for those who have driven BIG HP

[95CobraStang]

Hey Guys-

Well I'm putting together my engine for my '67. I have talked to a lot of builders and here is a general overview of what I'll be going with (I believe):

- 306 w/ twisted wedge heads
- comp cams blower cam
- all forged internal...
- KB S/C at 8-10psi (8.6:1 compression BTW) still deciding on lower intake

There is a good chance I will be dancing in the 400+rwhp range. Also, I will be sending the power through a build AOD w/ 2400-2600 stall.

To set up the question-- I havent driven a really fast car yet. The most powerful car I have driven is either a lightly modded '95 Cobra, '01 GT, or BMW 545i w/ the 340fwhp v8. I couldnt even tell which was faster since they all felt different. I have the BMW right now, and it will lay tracks for days in first gear, but it is so damn smooth that I cant tell if it is truly fast... shifts are too smooth.

My question: Is 400 rwhp completely ridiculous as a daily driver? What are some impressions as far as driving a fast car like that?

Will everybody who has driven a beast of a car let me know their #s (or est. #s) and give some driving impressions. They dont have to be 400hp either.

thanks-

I hope you guys bite on this topic...im interested here.

 

[hotrodredneck]

I had a 90GT with similar setup, but it has a 331, Twisted wedge heads, vortech renegade S trim, and a few other goodies on the engine...it also had a built up rear with moser 31 spline axles, auburn diff, and 3.73's....while I never did her dynoed before i sold her due to a new baby coming, and only being allowed to have 3 vehicles.....she was a beast....we estimated power to be in the 500 range...anyway, she was ok as a daily driver, but come winter time put it up.....and be prpared to spend lots and lots for gas.

 

[StangDreamin']

Not under-hood but......

All-new suspension and steering gear, subframe connectors everywhere, maybe even the full TCP "undercarriage cage". Strip and rehab the rear-end, from chunk to backing plates - maybe even invest in a Currie-built 9" with (as hotrodredneck mentioned) 31-spline shafts.

And, much as the sight of Foose "bling-bling" on each corner of a Classic Stang makes me want to ; I'd have to include some 17's and sticky tires - if only to wrap around some big-azz brakes.

EDIT: Hey hotrodredneck; looking at your sig, I've gotta ask if you (like SVTCobra306) are one of those guys who likes to land without an airplane for a living....
Blown up anything lately?

 

[hotrodredneck]

No, I was an Air assault soldier, no chute, just a rope....I work avionics on Helicopters.

 

[bnickel]

the only thing i've driven with that much power at the wheels was a buddies 68 big block camaro, it was a high 10 second car, and i can tell you there was a reason why that car was not his daily driver...geez, that thing was scary if the tires got wet at all, especially if it was only one side that got wet, nearly pissed my pants when that thing got squirrelly, i think he did too since he was in the passenger seat and didn't have the steering wheel to hold onto. yeah, gas was a definite problem in that car we used half a tank cruising around for about 2 hours. i will have to say that as long as you kept your foot out of it the car was fairly docile around town but it didn't have a blower strapped to it either.

another buddy had a built LS-6 in his 83 chev pickup that would fry the tires at 60 if he wanted to. never really got drive that one though, once i had to drive him home from the bar but i never really dogged it because i wasn't a whole lot better off than him, good thing we didn't have far to go. now that i don't drink anymore it's a wonder i didn't kill myself or someone else back then, glad i quit when i did.

 

[95CobraStang]

Gas guzzler...not really what I'm wanting to hear...shoot. I'll need to figure out a litle different combo then.... I forgot to mention - I'll be running EFI from early 90s stangs...maybe that will help some.

Which part makes the car eat up the most fuel?? Heads?? Cam??

thx

 

[hotrodredneck]

RIGHT FOOT....anything you do to make more power will make you use more gas.

 

[allcarfan]

400hp at the wheels is a STRONG daily driver. I wouldnt want to go anymore than that for a daily driver. Make sure you have the other components to support that.

Just take it easy when you first start driving it so you can learn what your car can and cannot do. This is what I did when I went from a 3.0 ranger to my lightning...just a slight difference.

I had a 624.7rwhp 1990 twin turbo GT....it was NOT EVEN FUN to drive ont he street.

 

[edgars23]

I have driven two cars on many occasions, both of them belonging to friends of mine, an 01 cobra at 430rwhp and a 460rwhp 03 cobra. They are fun to drive, but definitely not daily drivers due to how much gas they use. Hell, they would probably go bankrupt if they drove their cars daily.
Your setup will be even worse for a daily driver. These two modern mustang have big 13" disc brakes up front and 11.25" (i believe) out back, power brakes and rack & pinion steering, 17x9 (03 cobra) and 17x8 (01 cobra) tires with nitto dr's and traction control helps around town.
My 67 coupe is sitting around 300 rwhp and driving that thing around town is not fun in comparison. I desperately need to upgrade to all disc power brakes and rack&pinion steering and I highly recommend those upgrades as well as full suspension upgrades to you if you consider driving 400+rwhp daily.
-Edgar

 

[68keyblr]

I'm building a 331 for my '88 GT daily driver. I opted for the 331 because I am aiming for 350 rwhp without getting too radical. I may add a KB super charger down the road. I'm going with AFR 185 heads, 1.7 roller rockers, and a custom cam. My goal is 350 rwhp and 20 MPG (5 spd with overdrive and 3.08 gears).

My goals for this car seem to be somewhat similar to yours. Nice thing about the S/C is the power is only there when you floor it..you're not feeding the extra cubes when you are taking it easy.

I'd say 400 rwhp in a '67 would be more than a handful with stock suspension and steering. I'd definitely upgrade to rack and pinion steering, coil over or MII front suspension, and some BIG disc brakes. Maybe a 4-link rear end too.

 

[95CobraStang]

I have a front disc swap sitting in the garage...so it looks like I should get going on that right away

 

[Max Power]

I have about 450 at the flywheel, and a beefed up stock style suspension will handle things. I brake upgrade would be nice from the factory discs.

Don't drive it in the wet. There really isn't any point.

 

[65fastback2+2]

im going to say different....i think your setup is very streetable...but you need to make it easy to control...ive never driven more than 350hp....but my most recent ride along was about a 520hp 03 cobra....thing was a BLAST and the guy i rode with didnt have to do much to keep it straight and flying.

I would definitely give Ronstang a holler....he built like a 10 or 11 sec 1/4 car that got like 30-31 mpg on the highway....heres 2 things ive learned from him and others:

1) get a BOV that you can control from in car....when its wet out....set it really low so it lets go of almost all the turbo....turn it up when its dry and ready to haul butt

2) fully programmable ecu with that efi that you can select programmed settings from in car. Ronstang used this in that car i mentioned above....at the strip...they had a program they selected that dumped in tons of fuel, advanced timing and spark and made it a gas guzzling rocket....on the highway or around tune, they used a very lean fuel setting with timing taken out, etc....thats how they got 31mpg OUT OF A RACE CAR!

I say do it....just prepare ways to make it street or strip...make it adjustable

my opinion

 

[rbohm]

400hp is quite streetable depending on the combination. efi will help with fuel economy, but a conservative right foot will be very helpful as well. some other things to consider, if you use glasspacks or other loud mufflers, you will end up hating the car due to the constant loud droning of the exhaust. if you use highway gears with an engine designed for higher rpm power, you will have a bit of a time launching the car with a manual trans and that will get tiring. if you use an automatic with a high stall speed torque converter, your engine will be turning higher rpms than need be at low speeds, and that can also get tiring. too much rear gear, even with the o/d, also gets tiring.

you combo seems well thought out though, just remember to think through the suspension and chassis set up, and what tires you plan on running.

after you have the car on the road, drive conservatively and intelligently, and you should have few problems. you will have to be more attentive to your maintenance schedule than you would otherwise.

 

[classic boost]

1) get a BOV that you can control from in car....when its wet out....set it really low so it lets go of almost all the turbo....turn it up when its dry and ready to haul butt

that's just plain dumb. turbos are load dependant. no pedal, no boost. my tt 94gt made 500rwhp and ran 10.78@130. i drove it to work everyday for years. your right foot controls boost.

 

[65fastback2+2]

that's just plain dumb. turbos are load dependant. no pedal, no boost. my tt 94gt made 500rwhp and ran 10.78@130. i drove it to work everyday for years. your right foot controls boost.

unless you plan on shifting at like 1500 rpm for every gear....you will inevitably produce boost. In order to make the car move forward....right foot is needed....which controls the boost....BOV that is tunable could potentially dump ALL boost, which would alleviate the worry about accidentally producing some in the rain and spinning out and wrecking

i dont see how that is dumb

 

[classic boost]

unless you plan on shifting at like 1500 rpm for every gear....you will inevitably produce boost.

wrong. turbos don't 'accidentally' make boost. you have to ask for it. i can spin my car to 4k and not make any boost. besides, if the weather is so bad, and the roads so perilous, why would you shift high? i've NEVER made boost when i didn't want to.

 

[302 coupe]

unless you plan on shifting at like 1500 rpm for every gear....you will inevitably produce boost. In order to make the car move forward....right foot is needed....which controls the boost....BOV that is tunable could potentially dump ALL boost, which would alleviate the worry about accidentally producing some in the rain and spinning out and wrecking

i dont see how that is dumb

I don't think you understand how forced induction works.


As for the original posters question, 400 rwhp is not by any means ridiculous horsepower for the street. It will be fun, and you have to be mature in the way you use it, but go for it. I don't think gas mileage will be a problem, I'd expect mid to upper teens from it, even with a carb. Its just a 306 you know. Of course, some people only manage to get 8 mpg from a stock 2 bbl 289, which I still don't understand.

On the other hand, unless you frequent the track, its kind of a wasted engine. I see alot of guys at the track with 500hp running mid-upper 12's, other guys with 350-400hp running mid 11's. Your 400rwhp build isn't gonna hook up on the street very well, not to say its not a streetable engine, but if you can't put the power to the ground-then whats the point in making it.

 

[65fastback2+2]

I don't think you understand how forced induction works.

Turbos run off of exhaust....the higher the rpm...the more intake flow....the more exhaust flow...the more the turbo spools up....almost the same with a supercharger....the higher the rpm, the more the belt spins, the more the supercharger spins and makes power.

Granted, if you take it easy 15 pounds isnt just gonna pop out of nowhere on you....but both are going to add some boost at any rpm. I have a turbo F350 and a buddy of mine has a 04 cobra...both make some boost off idle.

The BOV was mainly for "Extra precautions"...to ensure you dont accidentally give it boost when on wet roads, etc.....im sure if you know how to drive your car really well, that is not a problem

 

[classic boost]

Turbos run off of exhaust....the higher the rpm...the more intake flow....the more exhaust flow...the more the turbo spools up

if that's the case, how come no turbo car will make any boost when you rev it in neutral????