beavers71

Getting ready to fire up new motor in my 71 supreme , got a few unknowns and maybe somebody can help me fill in the blanks ?
question is can anyone give me an estimate of hp/torque and max rpm for the following set up and how much NOS should I throw at it if any ????


70 455 (f1 ) block .60 over filled with hardblock
N crank balanced .10 under with billet mains and girdle
Teflon bearings threw out and ARP studs threwout
diamond pistons (bigger wrist pins ) 11.5 to1
eagle 6.735 rods
RR heads as cast milled to 65cc with girdles and roller rockers
.683/.683 mechanical roller cam 271/279@.50
1050 prosystems carb 1" spacer
2" kooks headers
Robb Mcc mechanical fuel pump

cutlassefi

That crank is only good to about 600 and you'll make at least that on motor alone. I wouldn't spray it all.

dmullin

That's an awesome bbo, let us know how that crank holds up. I wouldn't have the nuts to run a N crank with that.
I'm not saying it will come apart, but I wouldn't bet much that it wouldn't.
You'll probably like the heads. I do.

beavers71

max rpm ?

Fun71

OK, the nit-pick police have arrived.
600 thousandths over pistons are impossible, as is 100 thousandths under crank.
.060" over and .010" under are the norm.

We all know what you meant, but since I work with details like this I can't help myself.

I have nothing else to contribute. Carry on.

kitfoxdave

although the .600 overbore would be amazing... as long as there is enough metal left of course! ;-)

Octania

Do those digits around the decimal point really matter, or mean something? Huh.

Frankly, if it's too much trouble to learn it right, why not just leave out the decimal point and say "It's ten under on the crank and a sixty overbore" - then it's perfect. It doesn't say ten WHAT or sixty WHAT.

dmullin

In my opinion,
The engine will produce power beyond what I would think the bottom end should be subjected to.
I'd be afraid to go much past 6500 with what you described, easily passed with that induction system in a heartbeat.
Hopefully one of our Major engine builders will comment.
Hp: well north of 600. Torque: 600ish? IMO

beavers71

hook up to this motor have 400 turbo with a 5000 stall ati converter and 4.11 gear in the dana 60 rear , trying to figure 1/4 mile time with this driveline

dmullin

My GUESS would be low elevens/high tens. Not knowing the weight.
I'm assuming its a full weight car no a/c. Possibly faster with the right hook.

beavers71

got engine running sounds like a beast ! oil psi 65@idle hot engine got to 180 degrees, real snappy throttle response its like rite now.
Looks like i'll be calling Patrick from prosystems tomorrow about a few questions I have, back fuel bowl filled all the way up believe it should be in the middle of bowl and got to see what fuel psi should be at think it should be 7.5 off the regulator @idle ?

G Money

Did u get it

74sprint

What rpm a crank can take has 3 factors. 1. crank material and design. 2. reciprocating weight (pistons & rods, even crank throws). 3. cylinder pressure and where max occurs.


As far as a stock 'N' crank is concerned, I use stock cast pistons and stock rods and shift at 6,500 rpm, mind you I have on occasion have shifted at 7,000, because of race track rage. With the extra weight of your rods and pistons I would say that if you want to be safe it would be between 6,000 - 6,500 rpm. If you are a risk taker then go between 6,500 & 7,000 but, I would be checking the bearings after every race meet if you decide on 7,000 rpm. Oh and no NOS above 6,500 and if you spray then no more than 125hp shot. Watching your timing for detonation is critical do not let it detonate! it will crack the con-rod throws.


If you get the crank cryogenically treated then you can take all those max rpms up 500 rpm and NOS is limited to a 250hp shot between 6,500 - 7,000 rpm. The next biggest problem your going to have is the stall of your converter. You will have only 1,000 rpm to play with when you shift at 6,500, so the converter will come out of sync (lock out, when the stator and turbine are close to turning at the same speed) so you will be riding on the converter stall and making one hell of a lot of heat (slippage hurts ET & speed). Also that cam is like a 7,500 rpm cam, 7,500 rpm is forged/billet crank territory.


Ray

Fun71

Dude, this thread is over 2 years old.

wr1970

Lol

74sprint

Yup I did, It's going to take me 2-3 years to do my car, Mr. Moneybags. I've started a lot of engines on a stand and have seen a lot of people start them on stands and in the frame and it still took them years before it got to the street/track.


Ray