Which setup?

[XtremeModifier]

I have a 1987 Firebird Formula, bore 60-over, stroked, with a few supporting mods (cat-delete, switched to carb'd, etc.)

Glen, and others, I was wondering what parts I should get/which combination to run. It's a track-only car, budget of ~1k in addition to what I have.

350cid factory l98, bored 60, stroked with 400 crank, mild cam (regular over-the-counter autozone cam - edelbrock or holley I believe), cast iron heads, looks to be 23* heads. I have a holley 650 on it that's pretty junky, leaky jets, choke doesn't work, tune is way off, float's stuck, etc. Currently running Edelbrock Performer intake, the edge of the drilled holes for the mounting to the heads are sheared off, so I think I'll scrap it for the edelbrock torker2 intake (sell off the performer). What carb would go nicely with the torker2 on that setup? Also, what exhaust do you think would give the best bang for my buck? Currently running a 3" all the way to the muffler from the heads. Any suggestions on cheap mods that'll give me a nice gain in 1/4 mile performance?

thanks y'all.

[GlenB]

Bolt-on open loop EFI... kinda blows that 1k budget, but once you get it adjusted out it would be like always having the right carb every run.

[GlenB]

Well, if it is any help. I figure that engine will flow about 385 grams per second at a perfect 100% VE wide open throttle and naturally aspirated. I am assuming sea level, 8,000 rpms (drag racing obviously), 70 degrees ambient temp, and calling that 5.7L a 5.9L now to give it a little credit for being bored over.

What is you target RPM, altitude, average ambient temp, and I can recalculate it.

[XtremeModifier]

Actually, 6.4L is the 389 I believe...

either way, target shift point is 6000-6500 (depending on which it prefers...) altitude will be sea level (E-town is roughly sea level) ambient temp give 65 degrees (won't be running in sub-40, and it rarely exceeds 85) and humidity should be around 80% if that matters.

[GlenB]

Actually, 6.4L is the 389 I believe...

either way, target shift point is 6000-6500 (depending on which it prefers...) altitude will be sea level (E-town is roughly sea level) ambient temp give 65 degrees (won't be running in sub-40, and it rarely exceeds 85) and humidity should be around 80% if that matters.

Humidity does make a small difference. The program I use to calculate this from uses a default of 30% humidity. When I plug those new numbers in, that engine at 6.4l is showing to flow a maximum of 400 grams per second at 100% VE. An allowed tolerance is as low as 328gps.. if it were only running 79% efficient. A realistic best that you can hope for is about 90% VE which puts you flowing about 360gps.

I hope that helps to select the right carb. Picking an intake, carb, and exhaust combo that is designed to work at higher flow rates will likely produce lower power than a combo designed to work in that range.

[XtremeModifier]

time for some conversions. Thanks for the help though man.

[Starke]

Humidity does make a small difference. The program I use to calculate this from uses a default of 30% humidity. When I plug those new numbers in, that engine at 6.4l is showing to flow a maximum of 400 grams per second at 100% VE. An allowed tolerance is as low as 328gps.. if it were only running 79% efficient. A realistic best that you can hope for is about 90% VE which puts you flowing about 360gps.

I hope that helps to select the right carb. Picking an intake, carb, and exhaust combo that is designed to work at higher flow rates will likely produce lower power than a combo designed to work in that range.

what program do you use? IDS? MODUS? GENYSIS?

[GlenB]

The program I used to calculate this is on the web at D-tips.com. It is the MAF analyzer. It is really intended to help peg a bad MAF sensor. But if you play around with the inputs you can also use it to find VE of an engine.

If I want to measure VE directly on a vehicle and graph it out in one step, like I did in one of the treads here, I use Speed Tracer.... which comes free with AutoEnginuity software... autoenginuity.com. http://www.sromagazine.com/boards/glens-garage/99114-what-ve.html

I have also used IDS for graphing out my needed inputs to run through D-tips.com on line MAF analyzer.

[Starke]

sweet ill check it out when i get a chance

[XtremeModifier]

alright... here's the latest update on the mulletbird:

I went ahead, threw on a new 570cfm carbeurator, luckily it's the same size (as in I can use the same filter). Fired the car up, and it took a little work (no surprise, hadn't started her in a week) and then the battery takes a dump right then, so I got a new battery installed. Finally started (fired right up this time around) and she smoked a little (no surprise there ... been raining and it's probably water in the exhaust and intake from condensation) and then it starts smoking from under the hood. I pop the hood, and notice that I have (2) leaky exhaust manifolds. It's metal-to-metal, and the best estimate I got yet is $280. So, looks like I'll be down for a while... probably gonna wait and get both the manifolds replaced and a tune-up (carbeurator tune is the most important, maybe ignition timing too) done at the same time, save myself the trouble.

In the meantime, once I get the garage cleared for the car, I'll try and take a few pics (leaves falling all over the car ... *curses whoever put that tree there*)

[GlenB]

Have you checked with a machine shop about resurfacing the manifolds?

[XtremeModifier]

That's where I went. They said $280 to remove both manifolds and resurface, then re-install (with new bolts, of course).