OUTATIME GTA

iTrader: (2)

Just for fun, what do you guys think. ..

A stock 73 Trans Am 455 (not superduty) a/t
i think they are 270hp/370tq, 3900lbs??

vs.

my 89 GTA (single cat, listed below)

yes the 455 is quicker stock for stock, but say i throw on these planned mods. ..

- fully tuned, ignition, sfc's, airfoil
- cold air setup
- full exhaust
- intake runners

close? what else would i add to keep up/win?
just curious how our newer technology fares against the old.

ChillPhatCat

I say it's a tie... you probably end up with more Hp, but with the right tires the '73 will hook like a ****...

SOLID LIFTER

'73 T/A without a dubt.

Nonni

If I was into gambling I would put my money on the 73 455, it will win if it is in good shape. My brother has a 74 T/A, 455 and it much quicker than any LS1 car I have seen (ok, its not stock, but who is ).

Just race him and have fun

Nonni

OUTATIME GTA

iTrader: (2)

is it because they have such monster torque or what?

or were they underrated from the factory with those hp #'s as well?

SOLID LIFTER

They were under rated for insurance reasons, and '73 HP ratings were also NET ratings instead of GROSS .
Gross rating is when they used to dyno an engine with no acessorys on it (most shops still use this method of engine dynoing) and with open headers.
Net rating is the method thats still used today(for the most part at the factory) its dynoing a motor through its transmission with all if its acessorys and through stock manifolds and mufflers.I dont know if they still dyno motor trough the tranie today or not.
Net ratings knocked between 50 - 70 hp + ftlbs. off back then, now on late model cars its only about a 30- 40 hp and ftlbs loss.

OUTATIME GTA

iTrader: (2)

so it really has like 350hp?? that's crazy, that would mean the superduty had over 400. ..

SOLID LIFTER

No the Base 250 (net) hp 455 would have had about 320 hp, the 455 HOs of 71 +72 were down rated to 335 hp but they actually made about 360-370 (GROSS ) HP

About 390 hp, the SD had round port RA IV heads that flowed 20% more air on the in. side and 30% on the ex. side, it also had a bigger ex. valve than the standard 455(1.77 SD, 1.66 standard), The sd used the same cam as the RA IV w/ .470"in. / .470 ex. lift + .308* in. / 320* ex. adv. duration, The SD used a Q-jet that flowed 830cfm as aposed to the standard 455s 750cfm,it had hi flowing exhaust manifolds, the SD also had a Nudular crank, fordged rods and pistons, a reinforced block , an 80 psi oil pump, and a provision for a dry sump oiling system. considering that the SD ran 13.2-13.5 back in the day on $#!+ tires, an auto tranie,3.42 gear,a 3700 lbs. weight, and a sissified magizine writer driving, 390 hp is'nt that hard to swallow.

ps: some people say the SD had 450hp, but I HIGHLY dubt it, then again they run the same times or better than Hemi cudas and the LS6, So maybe Im wrong about that.