Re: Need some criticism on a build
[Re: Shatar4]
#2425348
12/29/17 01:57 PM
12/29/17 01:57 PM
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Joined: Jan 2003
Posts: 14,514 So. Burlington, Vt.
fast68plymouth
I Live Here
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I Live Here
Joined: Jan 2003
Posts: 14,514
So. Burlington, Vt.
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Have you run it yet?
If so, what does it not do that you'd like it to do better?
With mild gearing and stall, there isn't a lot you can do and not lose some of the street friendly nature of a build like that.
The one thing I wouldn't have done is used the open chamber heads with flat top pistons.
68 Satellite, 383 with stock 906’s, 3550lbs, 11.18@123 Dealer for Comp Cams/Indy Heads
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Re: Need some criticism on a build
[Re: Shatar4]
#2425541
12/29/17 09:31 PM
12/29/17 09:31 PM
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Joined: Jan 2005
Posts: 4,451 Michigan
MarkZ
Worthy
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Worthy
Joined: Jan 2005
Posts: 4,451
Michigan
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Whose rotating kit is it? Know what the compression is with those 88cc heads?
I just built a 400 based 512 with Edelbrock 84cc heads. Compression came out to 10.5 and used an Edelbrock Torquer 383 intake (single plane). If I'm missing any low end torque because of it I sure don't miss it.
1987 Fifth Avenue - 512/518/D60
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Re: Need some criticism on a build
[Re: Shatar4]
#2425557
12/29/17 10:47 PM
12/29/17 10:47 PM
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Joined: Nov 2010
Posts: 3,696 jersey
Spaceman Spiff
master
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master
Joined: Nov 2010
Posts: 3,696
jersey
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i had an RPM intake and 850 carb on my 526. switched to an M1, and a 1000cfm quick fuel carb. car was good before for a 4,600lb tank, but after the swap, it's an animal. change the intake and carb.
526 cubes of angry wedge, pushbutton shifted, 9 passenger killer!
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Re: Need some criticism on a build
[Re: Shatar4]
#2425585
12/30/17 12:52 AM
12/30/17 12:52 AM
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Joined: Feb 2005
Posts: 4,319 Prospect, PA
BSB67
master
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master
Joined: Feb 2005
Posts: 4,319
Prospect, PA
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Its okay imo. If it were mine I'd go closed chamber heads with zero deck piston with the right piston dish for about 10.5 CR.
I'd maybe consider a little less cam, or maybe more carb/intake. But this is picking the fly sh** from the pepper, and easy changes once you get it running to get it to match your objectives.
Last edited by BSB67; 12/30/17 12:53 AM.
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Re: Need some criticism on a build
[Re: Shatar4]
#2425633
12/30/17 03:39 AM
12/30/17 03:39 AM
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Joined: Jan 2003
Posts: 27,421 Balt. Md
383man
Too Many Posts
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Too Many Posts
Joined: Jan 2003
Posts: 27,421
Balt. Md
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My question is what everyone else is asking and thats why the open chamber heads ? Do you know the real comp ratio ? And you wont have good quench either. I dont know the specs of that cam off the top of my head but the rest of the combo is not to far from mine. But I use EZ heads and have 10.6 comp with quench and mine runs fine on 92 pump. I use more gear with 4.30's and a 30" tall tire and I may gear down as I dont think it needs that much to run the same et. I run a 9.5 Dynamic street/strip type converter that flashes about 4200 and works good at the track but drives around like a normal converter. I also run a dual plane intake but I use the Indy dual plane which has pretty good size ports and runners and I run a 850 Holley DP. I agree with others that mine may go faster with more carb but it dont run to bad with the 850 and has great street manners with it. But you need to know what your real comp is to start with ? Ron
Last edited by 383man; 12/30/17 03:40 AM.
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Re: Need some criticism on a build
[Re: Dragula]
#2425651
12/30/17 04:17 AM
12/30/17 04:17 AM
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Joined: Aug 2003
Posts: 3,245 Between a rock & a hard place
cudadoug
master
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master
Joined: Aug 2003
Posts: 3,245
Between a rock & a hard place
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Nothing like trying to inhale thru a tiny straw with a dual plane intake and small carb...
Even with a mild cam, I would be running a 950 carb on an open plenum intake. That will double the air flow the engine gets right there.
Shorten the timing curve to get as much initial timing as possible with a quick advance. Right after I'm verifying 0 deck and milling the heads to 79 cc.
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Re: Need some criticism on a build
[Re: cudadoug]
#2425749
12/30/17 01:01 PM
12/30/17 01:01 PM
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Joined: Jan 2003
Posts: 9,892 Weddington, N.C.
Streetwize
master
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master
Joined: Jan 2003
Posts: 9,892
Weddington, N.C.
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If it doesn't come up to your expectaions the first thing I would check is your ignition curve, Stroker BBM's with street compression ratios tend to like a fair amount of initial timing combined with a limited/shortened centrifugal advance that's all in by around 2600-2800, timing can make a huge difference in performance. Several Times I've seen guys who never really built strokers before get them running with 10-12 degrees and they start and idle "fine" but the power and torque just isn't there when they drive them....Fix the timing and "BAM"! instant stroker happiness.
Back before we had all the closed chamber head choices Diamond and I think KB used to sell pistons with a "qunch step" so technically is had a flat dome that would take up a good portion of the open chamber. I built a really nice running 508" RB with some well ported Stage V's that ran really strong with a mild Hydraulic roller. That beast is still out there somewhere, I need to check with Paul PHJ426 to see where it's at.
Was there any work at all done to the heads? With strokers picking up the mid lift flows (particularly the .250-.450 numbers) really helps the torque and HP curve above the torque peak. As I remember the OOTB edelbrocks aren't really "killer" at .400 lift but they are easy to improve with skilled bowl/runner work like you can get from Dwayne Porter. just getting from 260 cfm to 280 at ~.450 lift will really wake up a strokers power curve. And combined with a better/more consistent (than delivered OOTB) valve job helps the snap and response and can act like a bit more agressive cam profile with no downside.
The pistons are obviously not going to help you (just something for readers to keep in mind) but possibly swapping your heads for a closed chamber like these new TF 240's and either port the RPM or swap it for a Holley Street Dominator with a little port and mainly plenum work would likely help out immensely. A custom calibrated 950HP or 1000HP 4150 base carb would help the breathing up top, as said with a dual plane each bank is effectivly limited to seeing only 1/2 the carb so the combination of a small runner/port with a small-ish carb puts restrictions in series which makes matters worse.
See where your curve is first, try running something like 16-20 degrees initial and limiting total (initial plus centrifugal) advance to 34-36, I'll bet that will make a difference. On paper your motor should run strong.
Last edited by Streetwize; 12/30/17 01:23 PM.
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Re: Need some criticism on a build
[Re: Streetwize]
#2426099
12/30/17 11:09 PM
12/30/17 11:09 PM
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Joined: Jan 2005
Posts: 4,451 Michigan
MarkZ
Worthy
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Worthy
Joined: Jan 2005
Posts: 4,451
Michigan
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If it doesn't come up to your expectaions the first thing I would check is your ignition curve, Stroker BBM's with street compression ratios tend to like a fair amount of initial timing combined with a limited/shortened centrifugal advance that's all in by around 2600-2800, timing can make a huge difference in performance. Several Times I've seen guys who never really built strokers before get them running with 10-12 degrees and they start and idle "fine" but the power and torque just isn't there when they drive them....Fix the timing and "BAM"! instant stroker happiness. I was one of those guys. All I had built up to that point was stock stroke small blocks. I tried what I knew and 14 degrees initial. Ran like crap. Settled at 24 degrees initial with a total of 34 all in at around 3200. Absolutely fries the 285 Nittos. I could probably bring it in sooner still. More tuning for Spring.
1987 Fifth Avenue - 512/518/D60
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Re: Need some criticism on a build
[Re: Shatar4]
#2426228
12/31/17 10:15 AM
12/31/17 10:15 AM
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Joined: May 2004
Posts: 12,418 Taxes & Virus's R-US, NY
Dragula
I Live Here
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I Live Here
Joined: May 2004
Posts: 12,418
Taxes & Virus's R-US, NY
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After reading all the responses I guess the first thing is to get rid of the 88cc heads and get some closed chambered heads. I always thought that this motor never lived up to the expectations I had for a Stroker Motor and something was missing. So a recap is: Change the heads Change the intake to a single plane Change carb to a 950? Thanks for all the responses. I really do appreciate it Single biggest bang for the buck is the intake....Swap it, and jet the carb up and shorten your timing curve. A small carb really only hurts the top end. With the right squirters and jets, you can gain a bunch on the low end with what you have. An 850 will not have the size squirters or enough jet in it for that engine. We run #45's front and rear in all our stroker carbs once we get enough initial timing in them. #37 is the smallest we have run, and they are always lean that way. Heck, we have been switching them lately to 50cc accel pumps front and rear just to get enough fuel shot in these engines. THATS when we really see the 60fts come down...But don't tell Thumper... Shortening the timing curve varies depending on distributor, but the more initial timing, say idle around 22* and total in by 2500, the more fuel it will take in, and the snappier it will be. You will have to tinker to get this. We have used MSD and Firecore distributors, and both work well. Also, we have found ours like a lot of total timing. Not sure why, but my big 512RB had to have 38* total or it was .15 slower... A 505 should be a beast! Our 512's are really nasty for a simple RB stroker. They idle well, and just fry the daylights out of a set of tires or slicks, let alone what they run on the track. You gots to learn what it wants....read the plugs, put a wide band on it, try jet changes, tinker with timing....
Last edited by Dragula; 12/31/17 10:23 AM.
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Re: Need some criticism on a build
[Re: LaRoy Engines]
#2426276
12/31/17 01:13 PM
12/31/17 01:13 PM
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Joined: Jan 2003
Posts: 6,591 Canton, Ohio
Sport440
master
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master
Joined: Jan 2003
Posts: 6,591
Canton, Ohio
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Okay, so we are recommending going to a closed chamber head of 78-84 cc's and potentially bumping the compression to somewhere's around 11.4-12.1? I did the math before suggesting going to flat tops. going from a 88 cc head to a 84 cc head with a .060 gasket nets the same exact comp of around 11.1 He asked for criticism on the build, that's one of the things I would of done differently. I also asked what his main intentions for the build would be and didn't get a answer. the combo as it should be torque running sob.
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