400+ HP x 2300 lbs x 11 sec Feasability

-
M

Mopartist

Well-Known Member
Joined
Mar 19, 2006
Messages
75
Reaction score
0
Location
Bend,OR
Generally speaking; I have a 65 Dart that I'll be transplanting a 360 motor in with a 727 or 904. My goal is to have a street custom classic producing maybe up to 1.5 HP per cubic inch and get the little 2300 lb A body into the 11s in the 1/4 mile. Does it seem relatively feasable? Or am I off on my calculations? I'd like to keep the motor as dependable as I can. Will I have to stroke it up to a 402 ci? I'd like say "Money is no problem" but who can really say that? Certainly not me; but over a larger span of time; the bank account doesn't take such big hits. Little by little ya know? Opinions, expertice, and advice needed. Thanks in advance
 
it wont be to hard to do , it only takes 350 hp at the rear wheels to go 10 .90 s in a 2300 lb car ... 400 hp at the crank is easy 11 s get it to really hook and your in the 10s
 
Its entirely possible but......you will need a good suspension, tires,torque convertor, trans, exhaust, fuel system,ignition, and can you REALLY get that car down to 2300 with you in it? Yes its possible, but to do it in a comfortable street car its a whole other ballgame.

don
 
Mopartist, are you sure your Dart only weighs 2300 lbs? The last time I put my 66 on a highway scale I believe it weighed in at 2860 lbs, and that was without my fat a$$ in the seat, and about a 1/2 tank of gas. At the time I had a 318 with 904 tranny and a 7.25" rear end in it. With a 727 and and 8.25" or 8.75" rear end, it would probably put me close to the 3000 lb mark - still not including fat a$$. :)
 
i just had my 66 cuda on the scale at e-town, 3400 with me in it. 360 904 8 1/4 stock body and interior
 
Yer right; I generalized that weight a bit (a lot) too much. My cars stock weight WITHOUT me in it is 2360 (if I remember right) and that was with that big boat anchor slant 6 / 904. I think that motor was probably over 500 lbs. When I pulled it out;(without the tranny) the cherry picker was straining (might be bad seals I guess; but it's reletively new) Anyway; I'll be shaving weight; but prolly after the roll bar (cage?); frame connectors; bigger differential; etc; it'll probably be a couple hundred pounds heavier than stock; then with my weight of 185; I'm closer to a ton and 1/2. Is there a HP to weight ratio graph to be had in order to generalize a ballpark figure for performance goals? Seems like I saw one somewhere in my research. Sorry for the failure to realize the true ballpark weight
 
Is there an average rate of HP loss through the drivetrain w/automatic tranny? Thanks for the chart by the way!
 
With an automatic transmission the lost is said to be 16-20%. It may be 18-20% but to be safe I would do 20%. With that in mind I would say about 440 horsepower on the engine would put 352 at the rear wheels. With that amount I would agree with about 11.90s in your sight with the proper gearing and tires.
 
It is very feasable to do without stroking the engine. A 360 is capable of doing this. No need to stroke the engine. It can also be done on pump gas.

You'll need a 9.5-1 min. (Max for pump gas) ratio, fully ported heads, 1-3/4 headers, single plane intake would be my choice with a 800 cfm carb or well preped T-Q. The converter would be something I myself would order from Dynamic converters. The rear ratio would be a little high for hwy. use, but a ring and pinion of 4.56 and 30 inch high tires would be doable for short jounts. (Limited Hwy. use.)
The MoPar "tips" scection reomends the "657" mech cam @ .590 lift.

This engine should be well preped. Don't skimp on parts or there prep. Save the money on the stroker crank and build the 360.
Though the bennifits of added torque with a stroker are nice.
 
Great advice guys. Thank you!

65ABDYsm.jpg
 
The charts and calculators are handy, but you need to realize what they dont take into account. Namely, the rest of the powertrain, the tires, the noise, the street driving. At 355 to the tires, you will need to stick very well. Not radials, but soft race tires, with a really good suspension. Much more than a set of Dunlops and a pinion snubber. You'll need a set of gears that puts the engine in the right spot in the power band in the traps..that may be 4.10s or higher..May not be the best cruiser gears..and if you drive it mostly, the gearing can help or hurt the experience. You'll need a convertor that also puts the launch rpm where it will be most effective, and maximizes torq multiplication. That could be 2800 10", or 4500 8" that feels sluggish when just driving at part throttle. If it were me, I would use the longest arm (stroke), so the milder gearing and a lower stall design can be used. A mild 408, with the right convertor and suspension, will go faster than 11.90s in that chassis and be drivae/cruisable too.
 
Definately something to consider. Cruising the street; I wouldn't be too concerned about traction. probably just have a nice set of 15' wheels on 50 series tires. And then at the track (1/8th mile is all that is local) switch over to slicks. The 410 gearset is what I was figuring on. I'm not too savvey on Stahl converters. Something I need to research. I've got plenty of time. I'm in no hurry to get it all done, but am kinda making my shopping list so I can devise a good plan at this point. Thanks for the advice!
 
I am sorry but I dont think your car, or any A body is 2300 lbs close to stock form. 2800 lbs yeah Id beleive.. which is really light considering most Neons, Civics and Corollas are around the 2500-2700 lb mark. Hell any late model Camaro or Mustang would probably be 3300 + lbs minimum. So though I dont think your THAT light your still light especially compared to most new cars on the road. My 1971 Dart with no spare tire, 1/3 tank of gas with the stock slant 6/904 and 7 1/4 inch rearend was 3030 lbs. That also was with 50 lbs of AC and the power steering. Now its got the 8 3/4s, 4 wheel disk brake conversion and the 318. What does it weigh? Id guess 3100-3300ish. The rearend probably added the most weight and the disk brakes added some poundage too. I dont know for sure but I am spectical that a small block comes in heavier then the slant 6. Has anybody here actually weighed them and compared them ?
 
You must log in or register to reply here.
-

Back
Top