Hello! I've finally started the carb swap on my track car and I was just looking for opinions or comments on the engine combo. This is my first time doing a carb combo, so I'm looking for any opinions or comments on something I should do differently. Before mapping out the parts, I'll give you guys the goal for this combo. I'm looking for maximum torque and maximum throttle response. The car will be used for drifting, so I'm looking for a large ammount of torque to induce oversteer when desired (via throttle), and the best throttle response possible because throttle pressure (on the pedal) is used to control the ammount of oversteer. I'm aiming for a flat torque curve with an RPM range of idle to 6000 rpm. Having peak torque numbers are cool, but I'm more concerned with having a nice torque curve, aiming for 300 rwtq (or more) from 1500 to 6000 rpm when the motor is complete. The motor will be build in two stages, with the second stage being a nice set of aluminum heads. For now I need to get as far as possible with the stock iron heads (I know I wont reach my goals with stock heads hehe). Here's the combo of parts I currently have:

1989 L98 Donor Motor (350 Roller Motor)
Holley 750 cfm Vacuum Secondary 4-BBL Carb
Edelbrock Performer Air-Gap Intake Manifold
Pete Jackson Gear Drives
Hedman Shorty Headers (1 5/8th) - No y pipe, nothing ...

All I need to choose now is a cam and the motor will be going into the car. This would complete stage 1 of the build. But this is where it gets tricky. I do plan to get a set of aluminum heads later on down the road, so I wanted to choose a cam that would work with both my stock heads and 1.5 rr's, and the aluminum heads I want to get later and 1.6 rr's. At first, I thought the ZZ4 cam would do the trick since my final motor combo will sort of resemble a ZZ4 motor (350 hp motor). But not wanting to sell myself short when I eventually get good heads, I thought maybe the LT4 Hot Cam might be a better choice since thats the cam they use in the ZZ430 (400hp motor). So thats where I'm at now. I'm planning to get a LT4 Hot Cam and matching springs, and run them with the stock 1.5 rr's and stock heads for now. I'm thinking this would give me around 300hp. Then later when I get a good flowing set of aluminum heads, switch up to the 1.6 rr's and have a motor that closely resembles a ZZ430 and hopefully fullfills my goals. What do you guys think? Sound like a good plan? Or does anyone have any recommendations? Thanks!!

 

You might also want to look at the TPIS ZZ9 cam, which is not as agressive as the HOT LT4, but is better than the ZZ4 GM cam. Supposedly its a TQ cam that can put peak power around 5500rpm with the right heads and intake. I'm not a big fan of Holleys, but at least you are getting a vacuum secondary - DP are a PITA to get tuned right.

 

what heads are you looking at? i know you said aluminum in the future but which ones? this may help you choose your cam so you wont have to buy two when you decide to further upgrade heads later.

 

I'm not really sure what heads yet. They need to be aluminum because of the weight savings (going for a 50/50 weight distribution with this car). At first I wanted to go with the Corvette L98 aluminum heads with the 58cc chambers because it was the budget way to go, but decided against it for two reasons. First, I dont think I'll be able to reach my goals as far as 300 ft/lbs through the majority of the powerband, so I decided it would be a better idea to get some better heads that can flow more. I'm also considering possibly boosting the motor 6psi later in the future, so I need to keep the compression ratio in the 9.x:1 range (so the 58cc heads are out). So I guess I'm looking at a set of larger chamber (64-68cc) aluminum heads with the normal intake style (No Vortech intake styles). I know the large intake volume heads produce the most horsepower, but since I'm looking for alot of low end torque and power in the low lift ranges, I guess I'm looking for intake volume in the 180-200 range. So I end up with a nice selection of heads to choose from. The AFR's, Trickflows, Pro Topline, or World Products, but I'm not sure which ones to go with yet. I know whatever heads I choose will support the .525 lift of the Hot Cam with 1.6 RR's, so it shouldnt be a problem. For now I'm planning to use the Hot Cam with the stock 1.5 RR's (what is it, .492 lift?) and just change out the springs. But I was worried that maybe the overall combo of parts for this stage 1 of the motor build might be a bad match. Or maybe the Hot Cam might not be the best choice for my goals. Just wanted to see what you guys thought.

I'll check out that ZZ9 cam Paul. Thanks for the tip!