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Topic Review (Newest First)
08-07-2003 08:54 PM
elukas I'll be playing around with carbs until the cows come in, but that's a little easier of a swap to play with than headers.
07-31-2003 04:20 PM
2wld4u
Quote:
Originally posted by Super Streeter
First off,a real 540 hp is a tall order out of a 383 or even 406 on the street.Westech's dyno is a bit optimistic,so figure that you are looking at that engine being a real world 500 hp combo.The combo of a small carb and dual plane is a disaster.The split plenum of the dual plane needs more carb then a single plane,a lot more.In reality,that engine combo needs to spin 6500 rpm of even a bit more to make an honest 500 hp.I would want at least 800 cfm on that combo,even maybe a 950 hp carb.that combo should work best with at least 4000 stall and 4.56 or more gears.It isnt a very streetable combo for everyday use.I would run it with a gasket matched Victor JR or Strip Dominator,and an out of the box 850 double pumper with the correct jetting.I would also run at least 1 3/4 primary pipes and 3" exhaust.Good luck.
you know that is a good point, I found the best carb for my 355 is a 800 dp, The intake is a portmatched weiand stealth intake with a spacer and I have no problems and it runs great...
07-31-2003 01:35 PM
5-7heaven an old '56 chevy truck, daily driver. should run on 92 octane, idle like a stocker, except for that "defective pulley" noise(blower whine!)
07-30-2003 01:06 PM
elukas
Quote:
if you've conquered your traction/hookup issues, you're WAY past 12-second timeslips.
Haha, We'll see.

As for 12s, I was talking shifting a 3 speed 400 at 5500 rpms, with the miniscule torque converter I have now, and 3.08 gears.

Looking at different options for torque converters right now. I wanted to retrofit my 400 tranny with a switch pitch conversion and torque converter but the company's web site doesn't seem to be up any more.

A lot needs to be beefed up before I can try leaving the line at anything above 2000 rpms more than a few times.

Quote:
FWIW, i'm also using MAXIMUM OVERKILL(blown big-block), to reach 12.00 times. just doing it differently, and more mildly(RV cam/junk heads/2-600cfm carbs/2.69 rear gears..and a 6-71 supercharger.
Maximum overkill is fun. That sounds like an interesting buildup. What are you putting it in?

-Erik
07-30-2003 01:27 AM
5-7heaven if you've conquered your traction/hookup issues, you're WAY past 12-second timeslips.

FWIW, i'm also using MAXIMUM OVERKILL(blown big-block), to reach 12.00 times. just doing it differently, and more mildly(RV cam/junk heads/2-600cfm carbs/2.69 rear gears..and a 6-71 supercharger.
07-29-2003 09:07 PM
elukas
Quote:
JMO, since this is a strip/strip car, i'd experiment with single-plane AND dual-plane manifolds, different-size carbs, headers,etc
Can do. And thanks for reminding me that nothing has to be set in stone, 5-7 heaven.

Quote:
modifying hotrods/street-strip cars is an expensive hobby.
It is?

Oh crap.

And Super Streeter, thanks for the heads up on Westech's dyno. I'd never heard that before but it's good to know. And a real world 500 hp combo will make me smile from ear to ear so that's ok. I'm just looking for a street car that makes me grin and makes em spin. Strip wise just looking for mid 12s with the potential to go farther when I want to.

Please more comments from all you lurkers. Not that I haven't already gotten a good amount of feedback from these cool cats.

-Erik
07-28-2003 10:07 PM
Super Streeter First off,a real 540 hp is a tall order out of a 383 or even 406 on the street.Westech's dyno is a bit optimistic,so figure that you are looking at that engine being a real world 500 hp combo.The combo of a small carb and dual plane is a disaster.The split plenum of the dual plane needs more carb then a single plane,a lot more.In reality,that engine combo needs to spin 6500 rpm of even a bit more to make an honest 500 hp.I would want at least 800 cfm on that combo,even maybe a 950 hp carb.that combo should work best with at least 4000 stall and 4.56 or more gears.It isnt a very streetable combo for everyday use.I would run it with a gasket matched Victor JR or Strip Dominator,and an out of the box 850 double pumper with the correct jetting.I would also run at least 1 3/4 primary pipes and 3" exhaust.Good luck.
07-28-2003 03:43 PM
5-7heaven JMO, since this is a strip/strip car, i'd experiment with single-plane AND dual-plane manifolds, different-size carbs, headers,etc.

methinks you should try lots of parts out, and see for yourself. that's why modifying hotrods/street-strip cars is an expensive hobby.

trial and error.
07-28-2003 08:09 AM
elukas Thanks, 5-7 heaven and 2wild4u.

I hope it does peak below 6,000, because it won't ever see the high side of that number!

And just to clarify, with the pipes CLOSED and the current 2.25" dual exhaust, I expect a much, much larger hp loss, which until I redo the entire thing, I'm willing to live with, so long as I can open those cutouts at the click of a switch.

And bigger carb, definitely in the plans for the future.

This is a street-strip car so your intake mismatch comment hits me where it hurts

Everyone seems to tell me a different story. I try to listen to all of them. Every drag racer has a different preference. And every dyno operator. And every article writer and every magazine. What is the answer?

I've personally only had dual planes in the past, but I think I'm going to try the victor jr. for a while and if it's really too much of a hassle for the street, I'll switch over. The main reason is I'm hesitant to mess with any of the major specs like that. (Not that they know everything, it's just nice to have a real dynograph I can work from). The smaller carb and lack of spacer is a very temporary thing, so I don't really consider those permanent changes. All in all, the change in primaries was the only real change I was considering making and I'm still thinking that over.

-Erik
07-28-2003 05:54 AM
2wld4u I think to get the rated 540+ hp youll need 1 3/4 header's, along with a HP carb, (which can be substituted with a proform main body)
07-27-2003 03:03 AM
5-7heaven howziit guy!

JMO, you'll lose more than 50 HP engine size at 6000rpm,but not just because of the 1 5/8" pipes. the 383 might peak below that rpm.

from 1500-6000rpm, your engine will need 665cfm or more, and that single plane manifold will not perform its optimum as an rpm intake(or similar), especially with a teeny 600 carb on a street car.

my choice: 700cfm carb/edelbrock rpm intake(or equivalent)/1.75" headers/2.5" FULL exhaust system.

on DDD2000, the single-plane intake will show an advantage over the dual-plane, with any carb size from 390-850cfm. in reality, it would be a disappointing mismatch for a street-strip.
07-26-2003 09:13 PM
elukas I know, Roy, but thanks for reminding me. I'll ponder that, along with this primary dealie some more.
07-26-2003 04:50 PM
roys63 That is a HP series Holley a bit different than the street carb, just a thought to ponder.
07-26-2003 03:43 PM
elukas Thanks for your response, Luciano.

Yeah, I know the 600 cfm sounds too small to me too. I will definitely be stepping up to a larger carb in the future if not right away.

I was just surprised at the modeling program I have showing only a very small difference in hp below high rpms.

-Erik
07-26-2003 02:29 PM
lluciano77 I couldn't give you any estimates on the output of it, but that 600 CFMs just doesn't sound right. Unless you are just looking to roast the tires, I think that carb is going to be a little small, and it might have a little bit too lean of an idle circuit. I would get a larger used carb on Ebay. They are pretty cheap and if you don't think the bigger one made any difference, you can always sell it back to someone on Ebay, or keep it in case you add something else to your engine later that will require it.
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