Corz

after a couple hours of thinking i am still clueless as to go about getting more grunt from this car out of the hole.

as of right now i considered goin to a 1/2 inch carb spacer, but i noticed i only have 3/8" hood clearance :mad

here's my specs on the motor
327+.030
its been decked not sure on how much
10:1 compression
445/465 lift cam with 280 duration
1.94/1.50 heads with 64cc (stock rockers)
edelbrock performer intake, and holley 600cfm carb.
tranny is a stock th400 and rear end is 3.08 posi

i dont wanna change the gears or put a converter in it.. any ideas?

bence13_33

There isn't much else you could do other than going to a lower duration cam with less lift (but then you would lose a bit of top end). I'd say if you want low end grunt a set of 3.70 gears out back would really give you a kick in the pants. You have a torqey setup as it is with the 64cc heads and 1.94/1.50 valves. Almost any modifications on your engine results in trade-offs (i.e. sacrifice some torque here for more top end there and vice versa). You seem to have a nicely planned engine....why not make it really come alive with a set of 3.70 gears. I think you are missing the boat if you stick with the 3.08s. Just my opinion.

Corz

i kinda like the whole 20mpg deal with the 3.08s I'm affraid if i go to 3.70s then my gas gadge would drop signifigantly.. and i do a lot of highway drivin with it.. but i could always take them out

bence13_33

Yea, your gas mileage is gonna drop. You say you do "a lot" of highway driving? If this is the case don't go with the 3.70 gears, I would recommend 3.55s. I had 3.70s and driving on the highway was kind of a PITA....I was taching about 3000RPMs at 60-65mph. 3.55s are a good all around gear.

20mpg jeez....my L48 with 23,000 miles on it was getting about 14 or so. She was running a bit on the rich side though :).

Stingy74

A mild stall wouldn't hurt you that much. I drove everywhere with a 3000 stall. Granted it's a lockup but city drivng wasn't as bad as everyone told me it was gonna be and that was with 4.11 gears. I think B&M makes something called a Saturday Night Special that stalls around 1800-2000.

flynhi

IMHO, you have too much cam and you need a hi flo exhaust with x crossover.

Corz

i already have a high flow exhaust, and i dont think an X pipe would help much


[Modified by Corzvette69, 10:43 PM 4/1/2002]

Prufrock17

I agree with those who say gear it. With a cam like 280, you're building some top-end power. I wouldn't "switch" gears back and forth depending on how often you drive on the freeway. A gear change really isn't the most simple thing, and wouldn't really be practical changin the gears a few times a week. I have an extra set of 4.11's with 4 series carrier (3.08's use a 3 series carrier) if you are interested. Your car would LAUNCH out of the hole like ya wouldn't believe :D

Shark Racer

I disagree w/ Bence on the choice of gears. 3.55 is too much for a car that's frequently driven on the freeway. I drove my 'vette on the freeway every day w/ the TH-350 and 3.55s and absolutely hated it. Much better w/ the 700R4. My reccommendation is to wait, and get a nice gearbox -and- gears. You'll get some crazy low-end and pick up an overdrive too. If you don't want to spend for an overdrive gearbox, the 5-speeds have some pretty good ratios too.
I like my 700R4, and w/ 3.73s it's supposed to be a hot ticket.
-Steve

Larry B.

From the secs given I'd say that you have too much compression for today's fuel. To keep an engine from "pinging" you can retard the initial timing OR..... limit the total. Limiting the total timing allows you to have a reasonable amount of initial timing. IF you have the initial timing retarded to elimiate pinging then you will loose a bunch of bottom end power. Along with the cam you are using and the gears in you car it would be veary weak on low end torque. :jester


[Modified by silvervetteman, 4:23 AM 4/2/2002]

thejaf

Yes, that's also where I would start. My 406 has a long-duration (250 at 0.050) solid lifter cam, TH-400 with a stall, and 3.7 rear. It was a dog when I had 11.5 comp ratio, as the timing was backed down too much. Changed heads, now comp ratio is 9.7 BUT, with the help of Lars, I have some pretty good off-idle response now.

because my cam duration, it likes a LOT of initial timing. I'm at 20*. Obviously, you can't keep the original timing curve with this much initial. I also found that my total mechanical timing with a 406 of this compression is 32*. Anything over that, and I start to get detonation. that means that I have a total of 12* of mechanical advance. That's really not much, but hey, it works :crazy:

I would mess a little with your timing, but also remember you are literally pushing the envelop with 10:1 compression on today's gas. One tank of bad gas, and you're one sorry M'fer :cuss

Matt M

2 ways to go about it:

3.75" stroke- making it a 383 (compression would be almost 11 to 1 though)

or

overdrive trans and 4.11's

Matt

Corz

i guess I'll have to settle for gears and an o/d tranny swap :sad:

should i do 3.55s, 3.73s or 4.10s ?

Matt M

If you are going to run overdrive, go for the 4.10. Your cruising rpm will still be less than it is now.

I run 4.11's and a 200 4R. The trans has a .67 to 1 4th gear making the final drive ratio 2.75 to 1! The car has crazy off-the-line power and fuel economy is not bad at all.

Matt