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Discussion Starter #1
So ive been helping gmhg70 sort out his combo and it seems a new set of headers are needed.

Combo

383 sbc
210 afr Eliminator heads pt #1054
Edelbrock 2970 ( i think) intake ported by chad.
12.8 compression
267/[email protected] .670/.640 with 1.5's on a 109 lsa in on a 105 icl
1 3/4's primary long tubes

this setup is currently peaking at 6900 rpm. I feel it should be 7200-7300 easy. The old combo peaked at 7000.

The only things changed were compression, 11.4ish to 12.8. And the cam. Old cam was 260/[email protected] .050 .63X lift on a 109 in on a 105. It was also switched to E85 from 109 octane gas.

On the dyno these changes picked the car up almost 38 rwhp. Converter is also flashing an extra 300 rpm.

BUT, the car slowed down 2 tenths and almost 3 mph. Looks like the new cam isnt playing nice with the converter. Pep has decided its time for the right set of headers too.

Looking for opinions on what some of you guys would think nees to be built for it. Off the shelf 1 7/8's are the same price as custom built for his chassis over in Aussie land so hes gonna have the custom ones done.

What would you put on it to get it where he wants it rpm and hp wise? I have my idea in mind already but want other opinions

thanks.
 

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pig hunter
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i would look at the convertor before the headers.. the 1 3/4 header on that cid with a 210 runner head and that comp and power is fine...
 

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Imo dont thing your going to see great improvement if any with a bigger header on that combo..... Maybe e.t in collector length.

i have similar combo 406sbc change to 1 7/8 didnt see any improvement in peak or e.t

I would look else were
 

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Discussion Starter #6
Gotta remember hes in australia. Only 1 header bigger than 1 3/4 thats a shelf header for his chassis and they only do it in stainless. One reason its so expensive.

Already has a UCC converter in it so thats good. It just needs to be restalled.
 

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Imo dont thing your going to see great improvement if any with a bigger header on that combo..... Maybe e.t in collector length.

i have similar combo 406sbc change to 1 7/8 didnt see any improvement in peak or e.t

I would look else were
I know what you're saying but they say 30% more fuel in, with e85 . It's gotta come out ! It could make the difference , I don't know ?

Pep
 

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I wonder if it would respond to different collector extension lengths, to a great enough degree, to tip you off that it would need bigger primaries? More so than with regular gas vs E-85?
 

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I don't know , but by the time i get collectors , cut , weld the cost just goes up and then the headers on top of that . It's expensive enough with out testing other stuff on top !

Pep
 

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Back in 2002-03 I had a 422 that made a freckle over 600 on the dyno. I tried 1.75" x 3" collector dyno headers vs my 1.875" x3.5" collector chassis headers. The bigger headers were worth 5hp at pk hp (6000-6200) and gave up 10ft/lbs @4000. The biggers headers didn't catch-up till mid-5000rpm range. Just fyi.
 

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I'd try different timing/jetting/shift points to try and find the lost E.T. long before I forked over the cash for 1/8" larger primary tubes, esp. on a 383 turning 7k.
 

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Discussion Starter #14
The new headers for this are NOT being investigated for causing the ET loss. The converter is.

Bigger headers are being considered because of the LACK of RPM with the new camshaft and change in compression.

It should NOT have LOST 100 rpm on the HP peak. It should have picked up at least a couple hundred.

With the intake, head,ci, 267 degree intake lobe, it should be peaking at least at 72-7300 no?

I am thinking the header is a touch too small and thats why the hp peak did not move up like was expected.
 

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Discussion Starter #16
Back in 2002-03 I had a 422 that made a freckle over 600 on the dyno. I tried 1.75" x 3" collector dyno headers vs my 1.875" x3.5" collector chassis headers. The bigger headers were worth 5hp at pk hp (6000-6200) and gave up 10ft/lbs @4000. The biggers headers didn't catch-up till mid-5000rpm range. Just fyi.

No offense but youre trying to compare apples to oranges... Youre 422 @6200 is moving less air than a 383 @ the 7300-7500 rpm this engine needs to turn and make power at.

Car already has a 5000 stall...what this engine makes below that is pointless and if the bigger headeris equal to or greater than the small one by 5500.... GREAT!! Thats exactly what it needs and where it needs it.
 

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The car did not back up 2 tenths because of the converter or headers.
What's backed it up then ? On the chassis dyno between the e85 , comp and cam it showed 22kw at the wheels more . That's 30hp ? at the wheels or 40hp ? at the flywheel . Do you think that's a fair assumption ?

Even if the conditions weren't optimum (as we know ) IMO It should have run a bit better or the same at worse ???

Pep
 

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Discussion Starter #19
Chad, that too is on the list of possibilities..... Its an OTB 210cc AFR head part number 1054.

I didnt think itd be out of area at 600-610 hp at 7200-7300.... I know that it would be at its complete and utter Max limit to do it. Maybe i overestimated its capability a smidge.
 
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