BBC vs. forced induction LT1?

[Last Ride]

Okay, so this doesn't directly relate to C3's, but bear with me. I have an LT1 (genII) in my car. I want to dramatically boost the power in the car, and was thinking about rebuilding the LT1 and adding a ProCharger or turbocharger(s). Then I started adding up the cost. For what it would cost me to do this, I could build a big block. I could even get one of those Ram Jet 502's! Granted, the big block would be signifcantly heavier, but the forced induction would add to the weight of the LT1. I could also use an aluminum block for the BBC (probably not the ZL1 block, but something aftermarket). I am not superconcerned with mileage, but it is a street car. I looked at the Edelbrock fuel injection for the BBC as well. I want to maintain creature comforts such as AC, power steering, and power brakes. Currently, the AC is not even in the car, and I would need a custom system fabbed up for either motor. Any suggestions? Thanks a lot.

 

[AKRAY4PLAY]

what are your power goals?? what is your budget?? these two questions have a profound control over your options. BBC's are all torque and great if you can live with the weight. the ZL1 was the same weight as a regular small block car, so an aluminum head SBC would save you some poundage. what are your plans for the rear end and suspension in general?? is your LT of the generation that changed bell housing patterns?? what are your tranny plans?? lots of ways to go, a starting point is all that is needed, Brian

 

[Last Ride]

what are your power goals?? what is your budget?? these two questions have a profound control over your options. BBC's are all torque and great if you can live with the weight. the ZL1 was the same weight as a regular small block car, so an aluminum head SBC would save you some poundage. what are your plans for the rear end and suspension in general?? is your LT of the generation that changed bell housing patterns?? what are your tranny plans?? lots of ways to go, a starting point is all that is needed, Brian

Brian--
Let's see, where to begin... I would say that power goals would be between 500 and 600 hp. As for budget, I was thinking that to rebuild the LT1 (a 1995 Corvette motor) porting my stock heads would cost around $6000. Double that, and you get the blower with custom work to fit into my car. I figure another $1000 or so for miscellaneous things, so about $13,000. That would put me well into my power goals. I am pretty sure I could be well into building a big block for around that price (if not less). I could then sell my LT1 and computer and be that much more ahead. As forthe rear end and suspension; it's a Dana 44 with a 3.45 gear, a stock ZR1 suspension off of a 1991 Corvette. I might ditch the fiberglass springs in favor of coil-overs, and go with carbon fiber half-shafts. The transmission I have nowis the 4L60E that came with the motor. I was going to send it up to FLP for their upgrades (they have 4L60E's living behind 9-second rides). I know the BBC can be a pig, but if I could somehow manage an aluminum block, I wouldn't be that much beavier in the front (maybe even lighter with the upgrade in suspension). This motor is almost exactly what I want:

http://www.sallee-chevrolet.com/ChevyBigBlockV8s/502pfefi.html

The only difference is that i would really like to find an aluminum block solution. I know the ZL1 is listed on that site is exactly what I want, I can't justify the cost just to say I have a limited production motor! I would also wager that the RamJet would not fit under my hood. Okay, I have said a lot. Any more thoughts with this info in mind? Thanks again.

Bryan

 

[AKRAY4PLAY]

for 500-600 hp you don't need a big block. i am assuming you want to stay with fuel injection?? you can port your heads and intake for a lot less than $6000. serious head and intake work should be no more than 2k. bigger throttle body and injectors are another grand. you can stroke and bore your motor to 390ish ci for about 2k. heads and exhaust are your biggest thing. i have heard of LS-1 powered Camaros that are turning 1/4 miles in the high 9's and still have A/C and power windows that work. i think you can hit your power goals for about 5k max with your current set-up. going big block will get you there as well, but cost is usually around 7-8k for the motor and a tranny will be more. getting EFI will increase the costs as well. where in the rpm band do you want power and where do you normally run in the rpm band??

 

[Last Ride]

for 500-600 hp you don't need a big block. i am assuming you want to stay with fuel injection?? you can port your heads and intake for a lot less than $6000. serious head and intake work should be no more than 2k. bigger throttle body and injectors are another grand. you can stroke and bore your motor to 390ish ci for about 2k. heads and exhaust are your biggest thing. i have heard of LS-1 powered Camaros that are turning 1/4 miles in the high 9's and still have A/C and power windows that work. i think you can hit your power goals for about 5k max with your current set-up. going big block will get you there as well, but cost is usually around 7-8k for the motor and a tranny will be more. getting EFI will increase the costs as well. where in the rpm band do you want power and where do you normally run in the rpm band??

Yeah, I know I can hit that number easily with a big block or a forced induction small block. Here's the thing: torque. Say I build a 600 hp small block and a 600 hp big block. Generally, the torque curve on the big block will be far more flat. That is what I am shooting for. Look here for example:

http://www.diabolicalperformance.com/diabolical540.html

Would such a torque curve be attainable even on a forced induction small block? Now, about cost... for the small block I have $2000 for heads, $2000 for forged stroker internals, and $1000 for upgraded fuel injectors, etc. Then add in the cost of the D1 procharger kit for another $4800 plus the cost of an 8 rib pulley (I have spoken with several FI people on this and they say that for this kind of power, an 8-rib pulley is needed to prevent belt slippage) for another $1000. That is close to $11,000 without doing anything the upgrade the computer. For the big block, I know I could come pretty close to that price with the computer for the EFI. Then I could sell the LT1 and computer and make a little bit of money back. I think I can make a big block that weighs about the same as the FI small block when all is said and done as well. I have toyed with the idea of building a big block as I could amass parts and just drop it in when I am done. That would provide for an education as well as little downtime. I would think that the BBC would be a little more reliable as well since there are fewer moving parts, but the small block would be better on fuel (when not driven hard). either way, I will have to upgrade my tranny to handle the power. This car isn't a daily driver by any means, but I do want some measure of drivability for the street. Originally, my goal was for 10-second 1/4-mile times, but I am starting to shy away from that goal on a street driven car. Thanks for the input!

Bryan

 

[AKRAY4PLAY]

that changes a few things. i was under the impression you wanted to stay fuel injected and not really play on the track. send me an email, i was trying to send you a dyno print of my 406, but can't seem to import the pic. when lowering the ET's you need to drop weight more than increase power. it takes a bunch of hp to make up for the extra poundage of a big block. since your thinking of selling the LT, any route you take will be off set in price. the Camaros i mentioned earlier are not running forced induction. so that is still a cheaper option, but not the torque your looking for. a big cube small block is a great blend of two worlds. light weight, big power, reliable, no suspension changes, all the bonuses your looking for. there are several guys on this and other forums that are running C3's with 383's in the low 11's and high 10's. the theoretical numbers of my car are 10.18 in the 1/4, have not gotten it to the track yet, expecting something in the 11's to start off with until the chassis in tuned in and i can get traction. http://www.airflowresearch.com/, look at the dyno sheets for these small blocks, they came very close to real-world numbers from my experience. my 406 was right in line with another sheet they had posted, my motor was actually higher. what are the emissions laws like where you live?? Brian