cutlassefi

Hi Boys and Girls,

I have a couple builds going on and I wanted to fill you in on the second one (first one is already listed, 380 SBO). It'll still be a bit but here's the plan confirmed by the owner. The focus is as few custom pieces as possible.

DX Block, fully prepped and bored to 4.125 with a BHJ Bor-Tru and Honed with a BHJ plate.

Forged 425 crank ground to 4.00" stroke for BBC rods, counterweights cut as needed. (Note, the crank will fit in the block just like it is. The reason the crank needs to have the weights cut is because they will hit the underside of the piston on the pin boss).

Scat 6.135 BBC I beam rods with the small end bushed to a SBC pin size.

SBF165125F06 Mahle Small Block Ford big bore off the shelf pistons, 1.165 compression distance, 6.5cc valve reliefs, SBC pin size.

The estimated bobweight is approx 2000 grams. A stock rodded 350 Olds with forged pistons typically has a bobweight of 2250. This will be lighter than that even using BBC rods, go figure.

Hyd roller, probably a Lunati this time, somewhere around 226/231 at .050. Not sure if the block will be sleeved for .842 rollers or I may have a line on better than stock .921 rollers.

Edelbrock heads with light bowl work.

Port matched RPM intake

Holley Street Avenger 770 carb.

It will be dynoed.

Note; all my dyno runs are done at a water temp of 160 or better. There are some, who will remain nameless, that do them at water temps in the 120's. In my book that's cheating, period.

I'll keep you posted.

Thanks!!

oldsmobiledave

I do not see it listed so I will ask since many will wonder....does this compute to a final displacement of 428 cid?

cutlassefi

Yes, 427.65 c.i.

cutlassefi

Update, just got the pistons today. They are an off the shelf Mahle piston. This particular piston was redesigned about 2 years ago.
Look at the box design underneath, this is a strong but very light piston. Piston, pin, and rings weigh less than 575 grams. That's light!!

cutlassefi

Update,

Almost everything is done, we thought.
Crank is done, counterweights cut down, BBC rod journals and balanced. Block was cleaned, cam sprocket area machined, align honed and square decked. Next it went up on the boring bore with the BHJ Bor-Tru plate installed. This is where it gets more interesting.

I've mentioned many times that I believe the way I have blocks machined is the only way to do it. I believe that even moreso today.
This DX block has bores that are almost .040 off enter towards the intake side, .040!! Add to that they aren't perpendicular to the crank and it makes it even worse. We have to exchange the .068 over pistons for .098 over, just to get it to clean up, go figure!

So for all you guys that say "hey all I need is a good bore and hone" think about this for a minute. no matter what you pay, if it's not done this way it's a compromise, period.

And some other info, Mahle is making the next oversize for me for the same cost as a regular set so this 428 just became a 434. Plus they said they can go as high as 4.200 on this current die, something else to think about, hmmmm.

As promised I'll keep you posted.

380 Racer

Mark, anything good is never easy. Bummer.

VORTECPRO

Note; all my dyno runs are done at a water temp of 160 or better. There are some, who will remain nameless, that do them at water temps in the 120's. In my book that's cheating, period.


Are you talking about me or BTR? Looks like a nice build, its hard to beat that ring pack on the Mahle piston. Put some spring on it. I look forward to the test. How did that block sonic test?

cutlassefi

[QUOTE=VORTECPRO;464305]Note; all my dyno runs are done at a water temp of 160 or better. There are some, who will remain nameless, that do them at water temps in the 120's. In my book that's cheating, period.


Are you talking about me or BTR? Yes and anyone else that it pertains too Looks like a nice build, thanks its hard to beat that ring pack on the Mahle piston. I agree QUOTE]

Gotta check with my guy on the sonic test, I'll let everyone know when I find out.

VORTECPRO

Is the DX block a diesel or a 425, and why is it popular?

bccan

Deja vu! This is nearly identical to my build (I'm 1.105" w/6.2" iirc) except I have just a tad less duration & no bowl work or port match, had to have my Qjet.

I love the way it runs - practically purrs for normal driving & just might have an 11.99 in it if i can get that fuel bowl to stay full the last 150' of track.

I think your guy is gonna like it.

cutlassefi

Vortecpro-Hmmmm thought you fancied yourself as some engine builder, sound familiar? What, they don't have Olds' in Denver?
You deserve this response. Do a search dude.

Bccan- as you know gotta port match with this combo, otherwise I don't waste the time, and just a minor bowl blend.

Kyle's 77 Cutlass

DX block is a diesel made by olds. If you ever do an SBO with major whoop ***,this is the block you want.They are beefy, sold bid webs and I believe the cylinder walls are thicker

VORTECPRO

[QUOTE=cutlassefi;464321]I dont fancy myself knowing the casting for a diesel block, I guess I do now. Are they hard to come by? And how much? There where several diesel Olds in the wrecking yard where I got my customers 455 core, as with 425s.

VORTECPRO

Thanks!

Kyle's 77 Cutlass

And cutlassefi will be building me one, one day. Just not sure about the 380 anymore, maybe 396.

cutlassefi

The 428/434 combo is really the easiest, mostly off the shelf stuff.

380 Racer

Mark, what did you decide to do about the lifters? For my solid rollers, it was the easiest just to bush down to 842s.

cutlassefi

We're going with the .921 rollers. I've called Top Line, the old Johnson lifter company, and they said they can do the stock lifter with different valving. Should work fine.

380 Racer

You are getting things done!

380 Racer

Sorry I gotta learn to read everything.

olds 307 and 403

With the .921" lifters, you could go very aggressive on the lobes and not destroy itself. Sounds like this build is reasonably mild, probably not necessary. Good to know that option exists.

cutlassefi

But it's a roller Christian. That means it all depends on the roller diameter, not lifter bore size. This lifter still has a .700 wheel size, the same as the regular .842 hyd roller lifter.

Thanks.

380 Racer

Mark, where is that 380 build located? I know I read it but can't remember where I read it.

olds 307 and 403

See Mark, I didn't think of that, good point. Is there any advantage to the .921" lifter in a roller?

kitfoxdave

A buddy with CNC plasma cutter made these for me from stainless... they look sharp! I just have to figure out how to attach them to my valve covers!

gearheads78

That is sweet. I love little custom touches like that when done right.

61reoldsman

So what ever happened to this stroker build ,any new updates ?

cutlassefi

Yes, the 380 is going together as we speak and the DX is coming down the home stretch for machine work and will be ready for assembly very soon, had to bore it more than originally anticipated.
Here is how I have all machine work done.

https://classicoldsmobile.com/forums...explained.html

VORTECPRO

I noticed over on the BTR forum your said the 455 you did the intake test on was going back on the dyno this week with an 850, I was interested in the results.

11971four4two

Bruce please show us your set up for boring blocks of Olds
Thank You

61reoldsman

Are there any areas of concern with these DX blocks that one needs to be aware of ,like cracks in the blocks and can you tell with out tearing one apart ?

cutlassefi

LOL!!!! I got it, you're kidding right!!!!!!!

cutlassefi

Uhh dude, this ain't a torque plate. And you don't need the torque plate to bore a block, only to hone it. But you knew that right?

SBORule

What happen to my post, that you quoted ?



I know of machine shops that build racing engines, that use torque plates on both decks when boring cylinders on each bank, not just honing them.

cutlassefi

Explain the benefit there please.

VORTECPRO

Waiting patiently for the re dyno test of the 397 HP 455, that was going to happen last week, then maybe this week, well its Thursday, then the 380 small block dyno test.

cutlassefi

Simple, it's not my dyno, I'm waiting on his schedule. He had a week long Mopar Muscle mag build that put him way behind.

380 Racer

Yes Mark I read where your dyno guy was busy. I for one understand, unlike some people who think the world revolves around them.

cutlassefi

Update;

Here's the dyno sheet and video of one of the pulls. Listen to my dyno guy. We had the dyno programmend to start the pull at 3000. But it wouldn't start there. It didn't start until 3600 because it was making too much torque for the dyno to load at that point.

Engine specs are;

4.155 bore
3.49 stroke
Lunati Hyd roller, 216/221@.050, on a 111, in at 104. Lift is .546/.526.
compression was right at 9.0:1
Performer RPM, untouched
7a heads, bowl blended, dividers welded, crossovers filled. 2.00/1.62 valves, head flow numbers are here on this site.
Comp Roller rockers, 1.6
Quick Fuel 750 slayer.

A couple of points of interest.
We had .5" of vacuum at full throttle.
I installed a 1/2" open spacer, no change.
All pulls done on 91 octane Citco gasoline

I've pretty much always contended that the RPM intake is good for almost all SBO applications. Imo this confirms that. This is a mild build yet still made almost 400lb/ft of torque at 3600? I don't think that intake is too big at all. Do you?

Thank you all for your patience, especially Dave.

Thanks again!!

Pull video didn't load, not sure why. I'll try it again later.

coppercutlass

How did that quick fuel slayer work out. I been thinking about buying one Im just curious as to how good they are out of the box . Car craft said it was one of the best carbs for around 300 straight out of the box. Their testing was on a chevy now that you ran one on an olds your input would be greatly appreciated,