I have a engine I have been building and I was wondering how much horse it will be when finish and maybe estimated ET's??

350 tpi,450/460 cam-208/212 duration, 1.6 roller rockers,custom chip, 3:42 gears,5 speed,eldebrock intake, stock runners and plenum, ported 1.94 heads stock exhaust manifolds, 3in catback dynomax exhuast... If anything sounds bad together its because I am runnin out of cash for new runners and headers etc but I am thinking about swapping anyway!!

What's your opinion!!
thanks guys

 

92,

You'll get more HP than a Honda Civic, for sure.

Your mod list sounds O.K., but if you are looking for total HP instead of torque, you might want to rethink the TPI system. The stock intake and exhaust will not support a lot of HP gains, especially on a 350. They are pretty good to a 305, but not a larger displacement. As for the cam, there is more than the raw numbers to consider, since the area under the curve can change dramatically as a given lift and duration. And since I'm on the cam profile, instead of spending more money on 1.6:1 rockers, maybe you could just get the cam that provides the lift you need without the extra help from the rockers. That total lift range (.480/.490) is well within the common offerings from many cam manufacturers.

I didn't read in your post whether you are porting the heads or paying for someone to do it, but if you're doing it yourself, you need to keep the grinder handy for a couple more steps. If someone else is doing the port work, at the very least you should spend a few more dollars on a die grinder and port the plenum, match the intake base and runners, and open the stock exhaust manifolds a bit. It will only cost you your time once you own the grinder.

Beyond that, adding all that extra air with ported heads, a different cam profile (and hopefully opened plenum and exhaust) will increase teh fuel requirement to maintain the correct AF ratio. This may mean larger injectors or at least higher fuel pressure on stock injectors. The PROM tuning can compensate at most cruising ranges, but cannot increase the fuel flow much at WOT. Increasign the pulse width much beyond 85% duty cycle doesn't increase flow that much at stock pressures, and can get very hard on the injectors over time.

And you didn't mention the installation of screwed rocker studs, or cutting the valve guides for clearance, but at any lifts above 0.480" you need to at least check the clearances and should definitely consider screwed studs. Of course you're changing to larger valve springs with the new cam, correct?

The other wildcard is the "custom chip". That can make or break your setup. If done correctly, you can gain a lot of useful power on PROM tuning alone. With all you mods and efforts, a poorly written PROM can drop your power to below your pre-modification levels. Just make sure you are absolutely clear to the burner about the engine setup and what you expect from the car.

Realistically, a 350 TPI with an improved cam, mildly ported heads, and a freer flowing exhaust should put at least 310-320 out the crank. What you get at the rear wheels is a different story, dependent on more variables. Just changing to the stock L98 aluminum heads can get you over 300 BHP pretty easily.

 

i'd be guessing around 260 to 270hp with quarter mile times around 14.0 to 14.2.

 

TPI likes to make it's power as low as 5,000 rpm. A T-5 wants the power to be in 5000-7000 rpm, with the majority of emphasison 6000 rpm. You will have a great engine on the street, but your strip times will be dissapointing. A t5 would prefer a MiniRam setup, but a SuperRam would be a good compromise, (and best for a Th-700)

Scrap those headers!!!