OE Iron head 355 holden street/strip - 636hp

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Re: OE Iron head 355 holden street/strip - 636hp

Post by Carnut1 »

What, no super sexy ported intake and port pics? Awesome build Tony!
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Re: OE Iron head 355 holden street/strip - 636hp

Post by KnightEngines »

Charlie - intake is as cast other than a port match a couple of inches up the runners.
Heads are sanded finish, 40 grit intake and 60 grit exhaust and chambers with polished short turns. I dont think I have many pics.
Plain ol 45 deg seats, 35/45/65/80 valve job (my faux 50 deg valve job - acts like a conservative 50 deg valve job but with the durability of a 45) with the 80 blended into the throat and the 65 blended into the short turn. Exhaust is 35/45/radius. Both have radius chamber sweep cuts. Intake is .040 on the contact, exhaust is .050.
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Re: OE Iron head 355 holden street/strip - 636hp

Post by Carnut1 »

KnightEngines wrote: Fri May 18, 2018 9:55 am Charlie - intake is as cast other than a port match a couple of inches up the runners.
Heads are sanded finish, 40 grit intake and 60 grit exhaust and chambers with polished short turns. I dont think I have many pics.
Plain ol 45 deg seats, 35/45/65/80 valve job (my faux 50 deg valve job - acts like a conservative 50 deg valve job but with the durability of a 45) with the 80 blended into the throat and the 65 blended into the short turn. Exhaust is 35/45/radius. Both have radius chamber sweep cuts. Intake is .040 on the contact, exhaust is .050.
Similar valve job to my Dart 215's, has a pretty strong flow curve. thanks, Charlie
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Re: OE Iron head 355 holden street/strip - 636hp

Post by DrillDawg »

I only made the comment about MT as he advertised that headers like that would spread the power band and make the same or better power as conventional headers. Sweet engine and you make it look easy.
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Re: OE Iron head 355 holden street/strip - 636hp

Post by KnightEngines »

I'm forced to use a lot of tri-y headers due to space restraints, in my observation a good set of tri-y's will give up very little peak to 4-1's & do produce a wider curve that hangs on after peak.
Shelf tri-y's are often designed for mild street engines, methinks that's why a lot of people think they can't make power. But built with making high rpm power in mind they work pretty damn good.
The headers on this one are far from ideal, there is probably a solid 10hp hiding in a set of custom pipes, but that handful of extra horses would come at a significant cost so shelf pipes are fine!
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Re: OE Iron head 355 holden street/strip - 636hp

Post by cjperformance »

KnightEngines wrote: Fri May 18, 2018 7:42 pm I'm forced to use a lot of tri-y headers due to space restraints, in my observation a good set of tri-y's will give up very little peak to 4-1's & do produce a wider curve that hangs on after peak.
Shelf tri-y's are often designed for mild street engines, methinks that's why a lot of people think they can't make power. But built with making high rpm power in mind they work pretty damn good.
The headers on this one are far from ideal, there is probably a solid 10hp hiding in a set of custom pipes, but that handful of extra horses would come at a significant cost so shelf pipes are fine!
And got to say that unless its a real full effort streeter with money to burn good tri-y pipes are fine and also add some space for hot air exit around the engine which helps not turn the cabin into an oven like a real stuffed fit 4 into 1 set can. Not to mention the typical extra ground clearance we need with the speed humps and general road conditions here!
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Re: OE Iron head 355 holden street/strip - 636hp

Post by DrillDawg »

They look like well made pipes. Most tri-Y's are shorter than those and Mickeys, Mickey called the pipes that connect the collector to the primary pipes his power "Y". I think one of the 2018 EMC entries used some headers something like those and scored very well.
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Re: OE Iron head 355 holden street/strip - 636hp

Post by CGT »

DrillDawg wrote: Fri May 18, 2018 8:36 pm They look like well made pipes. Most tri-Y's are shorter than those and Mickeys, Mickey called the pipes that connect the collector to the primary pipes his power "Y". I think one of the 2018 EMC entries used some headers something like those and scored very well.
Yeah. It won 1st place.
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Re: OE Iron head 355 holden street/strip - 636hp

Post by KnightEngines »

Our strip opened up again finally.
1st meet out the place was packed, only got 2x runs & babying a whole new combo.
Turns out the barge weighs just short of 3800lb.
And IRS rear end
Ran 10.8 @ 126, with 1.57 60"

It's getting a "low hanging fruit" diet to try to get it under 3500lb & next time out we'll turn up the vac & use the rpm it can turn - short shifted at 7200 that pass, it'll et best closer to 8k rpm on the shift.
Also going from 3.9 to 4.11 gears.
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Re: OE Iron head 355 holden street/strip - 636hp

Post by steve cowan »

Tony,
Pretty stout for first time out,
Showing 600 on the slide rule for the mph /weight, I think once sorted 10.0s are on the cards.
Just looking back at dyno figures, 40 pounds oil pressure is pretty much standard or is it how you set it up.
Anyway nice work Tony, Pretty impressive
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Re: OE Iron head 355 holden street/strip - 636hp

Post by KnightEngines »

Dyno reads about 10psi low, not sure why!
It's got 60psi in the car with 20/50 oil.
I reckon we'll get it down to 10.3 or so next time out, from there it'll take some more refinement of the car to get down to flat 10's.
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Re: OE Iron head 355 holden street/strip - 636hp

Post by cjperformance »

Nice work mate. Irs and 3800lb , VT commo?
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Re: OE Iron head 355 holden street/strip - 636hp

Post by KnightEngines »

Vr SS with all the fruit, inc amp, subs & spare wheel in the boot!
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Re: OE Iron head 355 holden street/strip - 636hp

Post by Steve.k »

Tony nice job on holden. What year would those engines be? Seems like a healthy head for iron oem. I know nothing about Holden tec?
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Re: OE Iron head 355 holden street/strip - 636hp

Post by MadBill »

KnightEngines wrote: Fri Jun 28, 2019 7:25 pm Dyno reads about 10psi low, not sure why!
It's got 60psi in the car with 20/50 oil.
I reckon we'll get it down to 10.3 or so next time out, from there it'll take some more refinement of the car to get down to flat 10's.
Earlier you mentioned "turning up the vacuum". If you're running crankcase vacuum, remember that every 2"Hg. of vac. reduces the displayed (but not the actual) oil pressure by 1 psi.
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