Intro and current project

[jayb]

You can have a FT type casting machined as a FE. As in dissy bore.
My D4TE "SPECIAL" is machined that way. It has thick walls and extra webbing.

Hmmm, I didn't know that.  Any idea how often that may have happened Howie?  That would pretty much explain this block if it turns out to have good wall thickness...

[ScotiaFE]

I'm not really sure how common that may be.
I don't know what application my D4 block came in. I got it as a stock short block.

[turbohunter]

Ok got the sonic test back.
Bores are 4.115.
Getting some pretty "thick" readings like 150 to 200+.
but then there are one or two places under 100.
Sorry the pic is so small.
In case you're wondering, Dustin Lee is the young kid I'm having do the work.
He an up and comer that campaigns a digger in Top Dragster.
He runs in the 6.80s with it.
Used to work for my brother at SCE Gaskets.
Curious to hear what you guys think about the block.
As I look at it more, the two thinest spots are the top rear of cylinders one and two ( 87 and 94 ).
Every thing else is well over 100 (well, rear top of 5 at 103).
In talking with Dustin, I'm thinking about being conservative and honing the block to 4.12 with a 4.125ish stroke.
It is a truck after all and if this is a "special" block I'd hate to ruin it.

[jayb]

That sounds like a good strategy to me.  The thrust surfaces of the block look thick enough, but anytime you get a spot where the wall thickness drops below .100" you want to minimize any boring that is done.  4.12" seems like the right bore size to go to.

[turbohunter]

Curious about the amount of cam y'all think I could get away with.
The heads are stock D2s that have been cleaned up. The Performer manifold has been port matched to the heads.
I originally bought an E'brock performer cam because it's conservative and I live in LA and figured I could sit in traffic with no ill effects.
I'm curious if you think I could get a little more aggressive because of the stroke being added (also decided to go with a roller set up) and still have it be able to be abused in our lovely traffic.
The cooling system will be great. I have secured the big radiator and will install an electric fan set up.
Very interested in the water pump discussions that have been taking place here also regarding volume.

[drdano]

Is there a specific reason you're looking at the 4.125 stroker crank and not the 4.25?  The 4.25 stroke assemblies have really proven themselves the past few years.

[turbohunter]

Started out wanting the longer stroke, but seeing the results of the scan chose to be conservative and go with the more square set up in order to take it a bit easier on it.
Those two thin areas on one and two worry me a bit.

[turbohunter]

That sounds like a good strategy to me.  The thrust surfaces of the block look thick enough, but anytime you get a spot where the wall thickness drops below .100" you want to minimize any boring that is done.  4.12" seems like the right bore size to go to.

Roger that on the bore size, but what do you or any of the guys think about stroke. Is staying more square (4.125) easier on the thinner walled section of the bore than going 4.25?

[jayb]

The difference on the thrust surfaces between a 4.125" stroke and a 4.25" stroke will be very small, in my opinion.  I'd go with the bigger stroke; more cubic inches will always help...

[turbohunter]

Well, finally got the block back in the shop at Dustins'.
It seems the PO had it bored without a torque plate so it was a bit out of round.
The final bore size came out to 4.125.
So after talking stroke over with Dustin at length (4.25 vs 4.125) I'm going to go with his recommendation of a 4.125 crank.
Here is my reasoning.
I'm backing off a hair for longevity.
The thrust sides are good but there are those two thin sides to think about.
I kinda dig that it's a square engine.
It's a 4x truck so I'm not worried about getting as much hp as I can.
It's gonna do a lot of traffic in LA so cooling is a big deal.
With cooling and engine life in mind I'm going to spring for coated bearings all the way through it.
I've seen these things (as I'm sure you all have) after many runs down the quarter and they look amazing.
I realize it may be overkill but want the best for my baby.
Rod length at 6.8.
Pistons are custom dishes from Ross with a little extra skirt length to keep 'em straight.
Going for 9.5 compression
Comp 270 HR (#33-422-9)
PRW rockers and shafts.
Port matched Ed Performer.
Maddog fenderwell exit headers
Going to try to get away with a 600 cfm carb as I have a couple 4100s already. Fully aware that may be a bit small.
Going to dyno it for break in and to test carb, timing, etc.

I want to thank you gents for all your input. And please feel free to rip into whatever you want 'cause as I said I'm just learning FEs.  :-)

[bartlett]

I also like a square motor . ... 

I think the performer is going to kill hp ..... 

[turbohunter]

I think the performer is going to kill hp ..... 

Agree, if you're talking about a hipo street or race motor.
I went back and forth on that.
But I referred to Jays book and was surprised at the low end torque.
Since this motor is in a 4x truck and will never see 5k, the low end is really what I'm after.
However, Jay left the runners stock, as new.
I couldn't help but open them up and match the head ports.
Maybe I screwed the pooch, but the dyno will tell.
Thanks for your thoughts. I really do appreciate it.

[bartlett]

yea I had a performer on my last 390 and it had lots of low end grunt it died at about 5g ... for a truck I see no harm if its just a street truck.

[My427stang]

I think the performer is going to kill hp ..... 

Agree, if you're talking about a hipo street or race motor.
I went back and forth on that.
But I referred to Jays book and was surprised at the low end torque.
Since this motor is in a 4x truck and will never see 5k, the low end is really what I'm after.
However, Jay left the runners stock, as new.
I couldn't help but open them up and match the head ports.
Maybe I screwed the pooch, but the dyno will tell.
Thanks for your thoughts. I really do appreciate it.

FWIW, I often tell my story about the Performer (althought it was unported) on my 4x4 in the 80s when the Performer came out, I paid nearly 400 for one.  I raced home to replace my 428 PI alum intake on a 4x4 truck with 35s, a low compression 390, and a 204/214 cam.  I replaced the intake and lost so much power everywhere that I swapped it back the same weekend.  Later I put a stock Street Dominator on it and it again lost nothing and pulled to redline with a 270H cam.

Hopefully your porting helps, but in the end, my favorite manifold for street truck is a ported Street Dominator.  I run a ported RPM in my 445 pickup now, but only because I had it.  I much prefer the street single planes for part throttle drivability and ease in tuning with all the top end power that any other street manifold can give.

If you spent the stroker money already, that 4.125/6.80 combo will run great, but the 4.25/6.70 has no durability issues at all.  Heck I built my 489 in 2006 and its as fresh as it was when I bought it.

Regardless which way you choose, next spring you can always slap a 750 and an RPM on it, and you'll get another "new" truck and extend the fun another year

[turbohunter]

That sounds like a good plan, runnin' it for a while then swapping to see the difference.
As far as the stroke.
I know all you guys are saying the extra stroke won't make a difference, and I fully acknowledge you ALL know more than I do about these babies.
Call me chicken.
I've got two more at least to build in the next year or two, so I'll start to get some confidence. Prolly obsessing a bit to much on the thin spots.