I've posted it a couple times, but here it is again. Custom Vortech heads, holley 650 4bbl, performer RPM intake and cam, K*N AirF, Dynomax headers, and Flowmaster 40's. The setup is great, and should give me 375+ hp at the crank. More than enough for my likes. My question is this, what do i need to do to reliably pull 5500-6000RPM shifts, which is beyond the origonal redline of my 1971 L-48's engine. Distributer? New cooling fan that can handle the higher RPMs..... electric fan?? Radiator?? Also, i have an auto...:( Right now its ok, but will it last? I'm most certainly going to put a shift kit in, i can't stand the 4000 RPM shifts it makes! And i cant keep start in 1st and shifting through the gears myself.... i'm just not comfortable with it. I'm trying to keep my cost down, as i need a lil paint and chrome work on top of what i'm already doing next week. Any help would be appreciated. Also... what is the best guess at the stock weight of my car? 3300lbs?? Thnx

Brandon

|UPDATED|10/23/2003 5:44:28 PM|/UPDATED|

Any time you add increase horsepower you're also adding additional heat that has to be carried off by the cooling system. Whether your cooling system can stay within design parameters is a maybe. A lot may depend on how good your stock system is with its age.

You've done a lot of positive modifications to the engine, but didn't say anything about the crank. The L48 has a cast crank instead of forged like the L82 (which also has 4-bolt mains, the L48 has two). Not that it isn't strong, it's just not made to take the same stresses as a forged unit. I believe that cast crank is good to somewhere close to 400 horsepower, but I have no idea how much you'll be winding your engine out to the redline. You may consider a forged crank with ARP main bearing bolts. That should handle you power output quite well.


I think the curb weight of your car may be somewhat higher than 3300 pounds. The later C3's with impact absorbing bumpers and more emissions ewuipment ran the weight up several hundred pounds, so your guess may be in the ballpark.

Any recomendations on what crank to buy?? On another note, how much of a benifet would i get from balancing the crank i have?? Also, anyone have any added info as far as what i should do to beef up the electrical system? Thnx again,

Brandon

|UPDATED|10/23/2003 6:36:24 PM|/UPDATED|

You can check with any speed shops close to you about a crank, but just as a reference, Summit sells forged cranks for a 350 for about $590, and it's rated for up to 650 horsepower. Of course, you'll need bearings and seals and bolts that will take it. You may well be able to beat that price, but I just included it as a reference.

You definitely want the crank balanced...whether a new one or if you get your current one reconditioned. Once you go that far, it's foolish to not rebalance it. I've never experienced it, but I understand a crank out of balance is not a nice experience, especially when the rpm's are up, and the engine wants to tear itself apart with vibration.

I don't know that your electrical system would need beefing up. That really depends on the electrical load and accessories there, or what you may be adding to it. You could put a Powermaster or Proform alternator in the car, but make sure it was needed before spending the money on that...they sure are purdy though, being all chromed and all.

I have made similar mods to my L48. I used an Accel HEI distributor. I also swapped out the th350 for a beefed up 700R4 with 2200 converter. The rear gear was changed from 3.08 to 3.55. That made a good combo. Shifts are around 5800 RPM.

Owen


|UPDATED|10/23/2003 7:04:45 PM|/UPDATED|