Ok just a hypothetical question here, how much horsepower do you really need for a relatively quick street car without sacrificing drivability/reliability or breaking the bank?
I just trying to plan and budget for a project car I’m contemplating. It’s a 71 Demon. My thoughts are a new generation Hemi (5.7 or 6.1, kind of why I asking this question) and an overdrive automatic trans, with probably a 3.73 to a 3.91 rear gear. This car will be a cruiser with much more street than strip time. Drivability means more to me than outright performance. I’m thinking that about 400 hp would really be all that I would need without getting too exotic or expensive. Also for any A body guys out there that are running similar specs, any idea how fast would this combo be in the quarter?

Any thoughts???????

By the way I already know that
A: Too much HP is never enough
B: Speed costs money son, how fast do you want to go?

more power! grunt! grunt!

i would build a stought 408 stroker bottom end and just use the stock heads for now. put an air gap on it with a descent holley. Then when the 400hp feels slow theres a lot more to be made

thats what i wished i had done.

My 340 was dyno'd at 370HP and 407 ft/lbs of torque, and that's more than enough for me. Especially with gas at $4.60.

Jim

I guess that I should add I'm almost completely settled on a new Hemi, with fuel injection, a/c, power steering and all of the "modern" convieniences.
I've just seen a growing amount of variability with offerings for this engine, from a junkyard 5.7L truck engine to an $18,000 6.1L beast from a nationally recognized engine builder.
Thanks for your input!

Scott

as much as you can afford or until it scares you whichever comes 1st.

you didn't mention weight, suspension or tire size. If you figure around 3300, stock and the biggest tire is 27 tall, 8 wide, the 5.7 should spin them easily. with the deep rear gear and late trans, you should have gearing to pul smartly up to at least 90+. How much do you really need, and how are you planning on putting it down?

This must be a trick question, right?

A cam/headers 5.7 Hemi will do over 400 hp easily.

Pull a low mileage 5.7, sell the tranny, get a truck front dressing (accessories), get the TTI headers and the XV intake, put a cam and run that thing...really basic with LOADS of room to grow.


Go drive an LX car, and then imagine one with less drivetrain loss and 1000 lbs less weight. There are longblock cam and exhaust 5.7 cars knocking on high 12's @ 4000-4500 lbs...

We are putting a stock shortblock 6.1 into my friends 67 Charger with a carb based cam with worked 5.7 heads....it will fly, and we will detail the process to show how much power these motors will make on a budget.

https://board.moparts.org/ubbthreads/show...rue#Post4534456

I think any A-body + New Hemi is going to be a dynamite combo. I'm driving a 3600# Valiant with a low-squeeze 340 that makes an honest, untuned 300hp and 340lb-ft at the crank. With a 4-speed and 3.23 gears, it's a treat to drive - can spin the tires with ease, and has plenty of grunt. It's not the fastest car on the street at all, but it should crack in to the 13's. Add 100hp/lbft from the new Hemi and you're looking at 12's with virtually no down sides - except for initial cost, and complexity of fabbing up an injection system if you go that route.

IMHO, grunt makes the world go round. The HP will follow the torque if the breathing is there.

Clair

Always build more than you need. Remember, that's why we have throttles on these motors.

Depens on what you can live with regarding street manners in terms of idle and bucking at cruise speed. If you drive it regularly in heavy traffic you will want to take this into consideration.

400 HP sounds like a good number, should put most cars in the 12's. If you go quicker than 11.50's the NHRA requires you to have a roll bar and other safter equipment.

It really depends on how fast of a street car you want ?? If you want to beat alot of these newer cars then you might want to shoot for 11's. I mean I saw a Mercedes at the track running 12.40's that I believe was the supercharged V8 deal. I figure my 63 makes about 500 hp at the flywheel to push it at 3700 lb's to mid 11's and it really is a very mild 440 by todays standards. But with an A-body the smallblock stroker is the ticket. Very easy to get 450 to 500 hp and that would put your A-body well into the 11's and still be very streetable as you can do it with 3.91's as that's what my son uses with the 400 in his Dart. Good luck , Ron

I make 350hp and 400 ft lbs. from my 360 in my 71 Demon. With 3.23s its good for high 12's at about 105. Let me know if you want the engine combo

WOW!
This is why I love MOPARTS.
Lots of options here and lots of good feedback Thanks to all
I've been doing some additional reading on the 6.1 crate motor on a few other threads here and that sounds like a really good deal If the electronics all work out.
While I'm at it what is all of you opinion on an OD automatic trans? plenty of options here as well from a beefed 727 and a Gear Vendors Overdrive, to a TCI 4 speed automatic to the Chrysler 5 speed auto that will require floor surgery in an A Body. any suggestions?

I would run an overdrive in the demon if i had the money and could get one. Would love to have 3.91s or 4.10s out back all day long

Thats exactly my thoughts as well.
steep gears to get it out of the hole and still cruise at 70 mph at around 2500 rpm!
I'm just not sure which is the best option. I have not been in the market for a trans in about 15 years and things have changed!

gear and stroke have a relationship too.

you could use a highway gear and let the advantage of the stroke pull you forward. it will work as well as a gear multiplier.