351w, stealth or Performer RPM? etc.

Mosse · Aug 13, 2004

Hi guys,

I think it is time for my engine to have an upgrade.. The current combo is:

-Edelbrock 600 cfm carb
-Edelbrock performer intake
-Crower mechanical cam 212/216 lift around ,480
-Stock -69 heads with Screw in studs, guideplates, 1,6 alu-rollers
-Hedman shortie Swapheaders 1 5/8 and 2 1/2" pipes with H
-Mallory Unilite and Hyfire coil
-69 stock block, bored 030, sitting 1" lower than stock
-stock 4bbl bottom end with ARP bolts, 10:0?
-Toploader 4-speed
-8" with 3:00 gears

Car is run every day on street and sees some cornering tracktime.

What I was thinking of :

-Porting the stock heads (Inspection guys don´t let me change them to AFR´s), bigger valves 1,9/1,6(or 1,5)
-750 carb, Performer RPM / WeiandStealth, and a rougher cam matching these intakes. I don´t think I can even fit Airgap there under the hood...

Is changing to RPM intake killing my bottom end torque ( the car is -66 coupe weighting 2920lbs)?
Can the stock bottom end with ARP bolts handle 6000 rpm, and for how long(10000 miles?).
Cam suggestions? I need pwoer from 2000-6000, peak 3500-4000
Do I need to invest on 9" rear.. Wouldn´t like to(weight, cost, just rebuild 8")?

Thanks for any info...

ratio411 · Aug 13, 2004

IMO you don't need to go far into this combo.
I am sure you could do better with a different intake.
If you go with an aggressive dual plane, your torque will not suffer. Keep the cam. Even a mild cam will come to life with mods. Assuming you need a larger cam with a more aggressive set of heads or intake is a sure way to lose bottom end.
IMO you would see improvments with an intake, gears, and maybe LT headers (broader power band/torque).
The only thing there is the gears...
Your 8" rear is borderline safe with the combo you have now. The 3.00 gears help too.
If you either put more power to the engine OR install shorter gears, you should get nervous about the longevity of the rear.
So, you have the choice:
A) Be happy and make no changes and don't worry about the rear.
OR
B) Make slight changes to the engine and hope that the gain in power is enough to satisfy your cravings and not enough to worry the rear.
Good luck
Dave

SadbutTrue · Aug 13, 2004

get the stealth, i hate my performer heh.

edit: For good power, i would keep the cam, get a stealth/rpm (you'll need a drop-base air cleaner for them as well), and go ahead and get the 750. Should work out nice. I don't know if I'd be too worried about breaking the 8 inch, but if you don't have a posi you'll struggle to put the power down from a stop. Gears would also greatly help, but since your cam is mild your 3.00s might be okay.

Mosse · Aug 13, 2004

You are talking about reuglar one not he Performer RPM? I have the performer too, but don´t really know how much it restricts performance in my combo. But, if I´m going to get bigger valves and portjob for my heads, I´ll have to look towards Stealth or RPM.

ratio411 · Aug 13, 2004

The Performer not only has a very small plenum, it has smaller runners than a stock 4v manifold.
The RPM/Stealth style manifolds up the volume of both the plenum and runners to better support a higher power band.
You will notice little/no bottom end loss, a little quicker revving, and a little stronger acceleration after 2500 rpm.
This assumes you make no other changes.
Your cam is perfect for the power band that you claim as a goal. You just need some better breathing parts.
You will get your biggest seat of the pants jolt from lower gears, but that puts your 8" worries on shakey ground. The lower the gear, the weaker the rear.
Dave

351w, stealth or Performer RPM? etc.

Mosse

ratio411

SadbutTrue

Mosse

ratio411

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