I've been reading posts and spending many hours each week with the SEARCH function. I am close to getting most of the poor mantainance issues cleaned up and am ready to start saving up for the bigger drivetrain modifications; such as heads, headers, cam, PROM, etc.

I am really unfamiliar with GM V8 engines and there is so damn much to learn.
What I would really like to get help with is understanding what my 'Big Picture' should be.

This is a 'Play Car' for me and not a daily driver. What I dream about at night is a Camaro that dances around the back roads where I live (think of hwy 1 near the West Coast Ocean running from one end of California up to Canada).
I occasionally like to go drag racing, do autocrossing, and high speed dashes across the Nevada desert. I know that a drivetrain focused on one area is much easier than a 'do everything set-up. I invision in two or three years time, a supercharger finding it's way home under the hood. I don't need big block power, nor do I want to drop in a $10 grand engine. I do want enough power so that I can run into a corner deep and throttle steer the rear end out of it (power sliding). With the weight of these cars

What I've got to work with, besides a budget of $400 a month, is a 1988 T-Topped IROC TPI L98 700R4 9-bolt Borg with 2.77 freeway gears and approx. 150k fairly gentle miles. (wife bought this for me in January; no joke) It came with a recent full 3" exhaust system.


So far I've focused on fixing all the little worn out items, doing a full tune-up so I can have a solid base to spring board from and have amassed a bunch of parts to start installing(like Spohn subframes, completely new brake system, suspension pieces, Recaro seats). I pulled the plenum and cleaned out the throttle body, added a AFPR and set the initial pressure at 37psi. I've got a set of SVO 24 pound injectors waiting to be dropped in.

Some of my concerns/questions:
* What approx. horsepower will it take to be able to throw the rear end out while powering out of the corners: 300-325?
*At what point can I effectively have a PROM made up?
*If I can bring this engine up to 300hp, will I still need to drop the rear gear ratio?
* Camshaft with wide torque band?
* Should I keep this block or should I consider finding a used LT1?
* How much better than stock is the 113 Corvette heads? Is a masaged 113 that much different than a set of Trick Flow heads?
* I just DO NOT understand cylinder heads yet. Can someone give me a quick primer on what to look for to accomplish really strong mid-range horsepower?
* Compression ratio: what is the stock and why do the 113's bring it higher?
* For what I'm wanting to end up with; what is a max horsepower (crank) figure that I should be looking towards (remember, blower will be a couple years down the road.
* I live in California. While designing this drivetrain, is there anything I have to be really careful of to be sure I can pass our **** smog laws?

Am I missing anything???????

Feel free to comment on just one or as many items. I've spent untold hours using the SEARCH function. However, I've found that it's great for 'general' info, but am having issues finding specific factoids that apply to my overall plan. I don't want to end up buying the same part twice or more because I didn't plan well. thank you, Nitro

 

It's not the easiest way to make power but if you want an opinion I'll give you one. Smog restrictions are difficult, you want to be able to pass them and have good horsepower go find an lt1 out of a fourth gen f body and keep all of the emissions bs have a custom burn done on the ecm and you'll be around 300 hp or so without modifications. try to find a 93 as you will not need to change anything on the trans and it's a little easier to set up.

 

Actually, that's probably pretty sound advise. I do have access to a large insurance auction and would be able to look for a wrecked unit. Then I'd have the updated interior and all kinds of 'nifty' parts that would nickle and dime me to death. Plus it wouldn't be the first car that I gutted and then cut the remainder up with my trusty sawsall and $100 bucks in cutting blades!
I'm also checking to see if I can hire a major GM head builder to design a complete drivetrain platform that would work with my driving expectations. Thanks for taking a few minutes to share your thoughts; they are greatly appreciated.

Sometimes when a project has you spinning circles in an attempt to take care of so many little issues it's easy to loose the focus. Best of Luck on your ride,
Nitro

 

I'll try to help out. I'm no expert by any means, alot of other members here with much more experience/knowledge than me, so take it for what its worth hehe.

- Suspension and tire setup really plays into how the car acts when you drive it hard, but I agree 300-350 rwhp is a good goal if you want to have fun like that throwing the rear end out and throttle steering out of a turn. I think with a 245mm wide rear tire (stock) you could have alot of fun w/ 300-350whp.

- The heads and cam stuff. Here's the way I look at it (again take it for what its worth). I consider the cam to be the personality/attitude of the engine, and the heads are the muscle. So the cam determines how the engine acts, determines powerband, driveability, etc,etc. The heads would determine how much power the combo can make, how much air can it move and how fast it moves it. So to take it back to my anology, you could have an engine with a badass attitude but no muscle, this would be like swapping a LT4 cam into a stock L98. Or you could have a weak personality and alot of muscle, so this would be like swapping on AFR heads but running the stock L98 peanut cam. Neither of those setups are going to shine because they're mismatched. Having a badass attitude and the muscle to back it up, thats some power there, so aftermarket heads and cam. Of course it gets much more complex then that, but thats a real generalized way to look at it.

- The 113 Corvette L98 heads are aluminum with 58cc combustion chambers. Stock F-Body L98 heads are iron with 64cc chambers or larger. These numbers are generalized, I think casting differences can alter these numbers, nothing set in stone here. So to really know you'd need to have the machine shop measure whatever heads you have. But the CC's of the combusion chamber directly affects the compression ratio, along with other specs like bore size, deck height, headgasket thickness. There's a math formula you use to find out (don't remember it offhand). Stock iron headed L98's are usually like 9.3:1 to 9.5:1 compression ratio, the 113 headed L98's are higher, in the 10:1 and higher range because of the smaller combustion chambers of the 113 heads. Another thing that really matters when it comes to heads is the valves, really plays into how much air flows and how fast. Aftermarket heads usually have bigger valves than stock heads. The 113 heads are (I think) one of the best stock heads but IMO they don't compare to aftermarket heads that have been CNC machined and run big valves. I think 113's could provide alot of potential for someone that can port their own stuff, the rest of us will be paying to have them ported, so prices might be comparable to aftermarket heads that flow the same or better. Flow is what really matters, research that number to find the potentials. So all depends on what you want. I personally went with them because of the weight, not so much the performance.

- You could have a PROM made at any time but I think I know what you're getting at, you wanna maximize the cost of getting the new PROM made, don't want to be going back for new PROM's over and over. General rule of thumb, whenevery you change a component of the engine you gotta consider the PROM. The more extreme the part is, the more likely you'll need a PROM change for the car to run correct. Other parts that are not extreme might be considered computer friendly (aka works with stock PROM). Good example of this is cam selection. There are certain cams that work with the stock PROM and certain cam's that are too extreme for the stock PROM. So it all depends on what you change. I would say do the PROM changes after making big changes. Say you changed the heads and cam, perfect time to do a PROM. If you installed an airfoil or something, then probably don't need.

- Determining max power is kind of tough, especially with higher mile equipment. It all comes down to how the equipment was maintained over the course of its life. Alot of us are second/third owners, no idea if the previous owner maintained the setup perfectly. Best thing you can do is run a compression test to see the condition of the engine and go from there. People that build alot of engines probably know better than me what the limitations of the stock stuff is, but I personally think its around 385hp and/or 7-8psi boost. I think when you go higher then those numbers on a stock block then you're pushing it. Tuning becomes very important, bad tune will increase the possibilities of failure.

- I dunno much about SMOG laws but you'll probably want to build a combo of parts that are advertised as 50 state legal. So you wanna make sure the heads, cam, and intake are all SMOG legal and you wanna retain the SMOG setup, so you'll need headers with AIR system and you'll probably have to keep the TPI intake with the EGR setup. There is aftermarket stuff but it gets expensive.

I think the one thing you're missing is the rest of the drivetrain. Transmission and rearend should be considered since they get that power to the ground. I know first hand that high mile 700R4's are not the best setup when you wanna have some fun, I've broken a few of them myself. Rearends are also prone to failing, and I know you mentioned gear ratio, so you'll probably want to dig into that in the future. I would say determine if you wanna stick with an automatic transmission, and go from there. I personally decided that auto is no fun for what I want to do, so manual is my preferance. For rearends I think the stock stuff is fine for mostly anything except drag racing with alot of power and good traction (aka slicks). With street tires I think they're good to go, but if you're hardcore into launching the car hard then might want to consider beefing up the rearend too.

 

Wow, C.Hawaiian, as usual, your posts are thorough and well thought out; AND VERY DAMN HELPFUL!!!!! Thank you- Thank you!
Nitro

 

i don't have much to add to what CrazyHawaiian said other than about the prom part.
my recommendation on that is to learn to burn your own, you will get much better results than buying one mail order. they can get it close, but not perfect, plus they will focus mostly on WOT.

if you can do your own prom work, you can have a great idle, smooth part throttle acceleration, & a clean running motor that gets better gas mileage than what you would with a mail order chip.
on top of all that, any time you want to change something,.. you can make the changes to the prom yourself without having to wait weeks while they are working to get a new tune done for you.

for a little more than the price of a mail order chip, you can buy pretty much everything you need to burn your own & make any changes any time you want or need to.
there is a ton of info in the DYI Prom board up in the stickies that can probably answer pretty much any question you have.