XFI467 cam with Stock Heads, Ported Intake and 58mm TB, good idea or no?

[HotRodV6]

Ok, i just recently picked up a low miles (66K) 97 Firebird automatic car. The car has been sitting up the last 2 years because of a bad fuel pump and then a few months ago all the tires got slashed, so the PO was tired of messing with it and i picked it up for a very good deal.

As the car sits, it has BBK headers, and a flowmaster muffler, LT4 Hot Cam, 1.6RR, Moroso CAI, Eibach pro-kit springs and Bilsteins, Granatelli Motorsports rear lower control arms and panhard bar, subframe connectors and front strut brace. PCM has been tuned by the guy that builds the OBD2 cables. Front C5 brakes and 17x9.5 ZR1/Corvette GS Wheels and i just put new 275/40 tires.

As far as i can tell the rest of the car is stock, and according to the PO the last time at the track the car ran 13 flat.


Now, i have a nice pile of LT1 parts Ive been trying to sell from an S10 project that is now getting a vortec 350 and have been thinking about doing some parts swapping. I'm wondering how well the Comp XFI467 cam 230/236dur@.050 .570/.576 lift with the 1.6RR on a 113LSA will do with the stock unported heads but with a fully ported intake and 58mm TB. I also have a set f 643 casting heads that have been mildly ported and new 2.00/1.57 valves to go in them, the valve job needs to be done.

Just wondering if doing the head swap is worth it for the XFI467 cam, or will the stock heads flow enough, im also not planning on getting into the stock bottom end right now, so i know ill have to watch the peak RPM but was thinking it should be safe to 64-6500 RPM with a 2800 converter and the car already has 3.73 gears. I have a set of Lucas 42lb injectors and would also get it tuned for the new cam.

[englundjd]

I'd put the ported heads on it just for kicks... That cam will enjoy more head flow.
You will most likely be fine with the 24# injectors.
Might go for a slightly bigger converter.

Is the exhaust 3"? If not I would invest in a 3" catback exhaust system. Also a real set of headers and a 3" y-pipe would be a good addition.

[BALLSS]

XFI cam has aggressive lobes so GOOD valve springs are required. I run, with my XFI, the Lunati #73925K5 spring kit. Got it from Lloyd Elliott.

will the 467 work with stock heads, yeah...but as mentioned it would like more than stock heads.

42 lb injector is way to much...tuning may tame them but you would be better with the 24's (read less fing around taming the 42's down in a tune). If you could find some 30's like the Ford SVO red tops, that would be good.

[Revolutions]

I have to disagree on the 24# injectors being enough. Using conservative VE numbers (80%) and an A/F of 12.7:1 they will be at 100% duty cycle before you get to 6400 rpm.
I would very much prefer to loose a little idle quality with a 42# over run lean and hurt the motor with a 24#.
I have been doing Performance Trends simulations with that exact cam on a 355 and am seeing VE >100% from 4750 to 6250 with ported stock heads 270/190cfm, ported stock intake, 1.75"x32" long tubes and 58mm TB.

For reference:

intake & exhaust tuning	VE@ max power
None (2-stroke & Wankel)	55%
None (4-stroke)	75%
Mild intake tuning (4-stroke)	80%
Mild intake & exhaust tuning (4-stroke)	90%
Tuned	95%
Fully tuned	100%
Best	110%

[Dan]

You are playing Russian Roulette spinning the motor to 6500 on a stock bottom end.

[joelster]

You are playing Russian Roulette spinning the motor to 6500 on a stock bottom end.

I spun mine to 7k hundreds of times. Depends on how well it has been maintained and how good the oil pressure is.

[gmpowered]

I have to disagree on the 24# injectors being enough. Using conservative VE numbers (80%) and an A/F of 12.7:1 they will be at 100% duty cycle before you get to 6400 rpm.
I would very much prefer to loose a little idle quality with a 42# over run lean and hurt the motor with a 24#.
I have been doing Performance Trends simulations with that exact cam on a 355 and am seeing VE >100% from 4750 to 6250 with ported stock heads 270/190cfm, ported stock intake, 1.75"x32" long tubes and 58mm TB.

For reference:

intake & exhaust tuning	VE@ max power
None (2-stroke & Wankel)	55%
None (4-stroke)	75%
Mild intake tuning (4-stroke)	80%
Mild intake & exhaust tuning (4-stroke)	90%
Tuned	95%
Fully tuned	100%
Best	110%

I agree I can't stand people doing cam swaps running the crap stock injectors.
You want head room be it a fuel pump or injectors. Keep good fuel pressure and stay under 80% duty cycle.
The 42s are fine even the junk lt1 pcm can run them.

I spin 64 6500 on a stock bottom end. White oil pressure spring stock pump

[MoeHorsePower]

Idle quality does not suffer with any size injector if its tuned right, I had pulled my supercharger off before I installed the turbo kit, I drove around with 75lb injectors NA, absolutely no problems and still got 24 mpg on the highway...