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Here are some new & old pics of my parts I am slowly gathering to build my turbo EFI engine.












MBHD


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Hank I don't see who your going to get that clifford intake to mount to That 12 port head. Besides The mounts the ports are spaced wider apart.Or was the intake just a opps photo?


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hank, that is some pretty stuff you are collecting. i appreciate the head pics, esp.
do you plan on running the SPA turbo manifold?

twisted, i think he is going to run a standard head w/ clifford intake, first. then switch over to the 12 port head later. tom


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 Originally Posted By: tlowe #1716
hank, that is some pretty stuff you are collecting. i appreciate the head pics, esp.
do you plan on running the SPA turbo manifold?

twisted, i think he is going to run a standard head w/ clifford intake, first. then switch over to the 12 port head later. tom


Thanks guys,
Tlowe is correct, I plan on running the Clifford intake & SPA manifold on the engine in my Camero first,get somewhat familar w/my SDS EFI. Do some tuning,dyno it & so on. ;\)

Later, build a stronger shortblock & use my 12 port head.

MBHD


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Hank how far back into the runner did you go with the divider?


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3/4 -1" range.Can't remember right off the top of my head.

MBHD


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The main reason I put a deviders in was in hopes to increase velosity because the Clifford intake killed my low & mid range as compared to the Offy intake. 250 CI engine.
MBHD


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as thin as they look did they really do you any good??


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Yes it did help,if you made them any thicker @ the entrance to the port window that would make it worse.

If you made a dividers that was thicker @ the 4 BBL base ,then made it gradually thinner torwards the port that would have been better.
When you make any devider thicker @ the entrance to the intake port,it makes the window too small & will flow less.

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Question, If the piston motion pulling on the valve area through the port volume is what makes velocity in the port, how can the velocity increase if the divider is only in the manifold ?
Would not the siamesed port pull on both the manifold ports equally ?

MBHD is your head divided ?

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My head is not divided.
The other main reason for the divider was in hopes to create better fuel distribution,so the air fuel mixture does not stay on the outer part of the intake. To possibly feed #'s 2 & 5 cylinders better.

The velosity I would say did not increase,if any,,but I believe I got a little better fuel distribution.

I installed my upper port lumps & that did increase the intake port velosity.

MBHD


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MBHD

Hmm let compare build cost and outcome once your done.

Todate I'm at $3600 in parts and labor on the 4.2 turbo build less the cost of the turbo as I had it from the 292 effort.


51 GMC 4.2 turbo
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 Originally Posted By: efi-diy
MBHD

Hmm let compare build cost and outcome once your done.

Todate I'm at $3600 in parts and labor on the 4.2 turbo build less the cost of the turbo as I had it from the 292 effort.


I am not tring to build a low dollar turbo set up.
My SDS was $800 new,new SDS turbo exhaust manifold $180,fuel pump $200 injector bungs $30 ,304 stainless downpipe w/racegate $410,used injectors $100 w.flowtesting.Ceramic coating SPA manifold $40
new62-1 Hybrid BB turbo $900.
new 3 bar map sensor $40.

I still need to buy the fuel hoses & fittings ,Approx $250??

So far the total is approx w/these numbers $2,890.00.
Still not done getting more parts & odds & ends.
I am installing these parts on my used 250 engine.

MBHD



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efi, if we were into building it the cheapest possible. would not it be cheaper to build the V8?
you and i will both agree that we are after the odd power plant. yours is just more technically ahead. in fact by light years. i have still never sat down and added up the parts. i guess i do not see a reason as i am happy with the output and outcome. a nice easy starting, powerful engine. that also idles nice (alittle loud at idle with no muffler). tom


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Tom,

Agreed a stout 350 could be built for $3K. But we're a stubborn bunch that want to be different.


51 GMC 4.2 turbo
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efi-diy
do you have your engine built w/forged pistons,aftermarket camshaft,etc?
Basically,what all is done to your long block?
MBHD


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Ok

Here's a break down todate:

J&E pistons with rings and pins - $1150

Crower rods - $1160

Darton sleeves - $775

New 72# injectors - $450

Tial wastegate - $200 + 50 for the missing parts

Cam blanks - $400

Ooops mental calculator missed a bit total to date $4185


This is bulk of the hard parts - leaving valve train parts - valves, springs, retainers and better roller followers to come.

Turbo exhaust manifold - cost TBD.

Cam grinding is still spendy $900/pair but its coming down.

Other misc. items copper head gasket $50 head and main studs ~$80

Machining will be the next biggest cost. Labor here is not cheap - a typical machinist makes $45/hour here. But shipping elsewhere is equally expensive.


51 GMC 4.2 turbo
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What turbo are you running & cost?
Any cylinder head porting?

MBHD


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MBHD..

Well from above..

The short block is getting re-sleeved with Darton sleeves, J&E forged pistons, custom crower rods. Main and head studs are being installed and this has to be done on a mill so its $$$. With an aluminum block you need to roll tap the threads to get strength in the material.

If you wanted to build a mild turbo motor then you could use the stock short block, if you kept the boost under 7 psi and power under 450 hp the stock parts most likely be fine.

Getting the head ready is spendy as we need 24 valves and related parts - so 12 x inconel exhaust valves, 12 x SS intake valves. 24 springs, retainers, 24 spring seats. But its the head that make it worthwhile - the intake flows like crazy.

Cam blanks are only available as billet blanks with round lobes so it takes a lot of time to get them ground into lobes. Thus the price to turn the blanks into cams.


I hate breaking stuff so I typically built the strength in from the get go that way I'm not be restricted on what I do later.

I'm aiming for 28 psi...


As a side note Glen Self set the F/EA record recently with a NA 4200 ... 7.98 @162.63

That a fast inline.....

Last edited by efi-diy; 05/06/08 01:54 AM.

51 GMC 4.2 turbo
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And your turbo size & $$$?
How much HP are you planning on running?
All this into a 51 GMC truck?

MBHD


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 Originally Posted By: Mean buzzen half dozen A.K.A. Hank
What turbo are you running & cost?
Any cylinder head porting?

MBHD


Its a Garret GT40-88 to start - I may run out of turbo... \:\) it was $975 new.

Well 750 crank HP should be doable, yep all in a '51 GMC.... but I'm going to work up to that level. \:\) It may get a stint at B ville in some a little slicker..

The '06 head is way better than the '02-05 but they can be made to work . I'll be porting the exhaust port to match the exhaust manifold and blending the bowls into the runner as there is a sharp ridge in the bowl/runner transition. I'm starting with the '06 head.

Last edited by efi-diy; 05/06/08 02:09 AM.

51 GMC 4.2 turbo
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Cool,just wondering what is different w/the 06 cyl head?

MBHD


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Bigger valves on both intake and exhaust, MUCH better exhaust ports and deeper spring pockets so you can bolt in .500" lift cams without much work. In stock form it gets a bigger intake cam. The '06 motors were 290 HP from the factory in full emissions trim..


51 GMC 4.2 turbo
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