"THIS IS A RACE ENGINE AND DOES HAVE SOME BLOCK FILLER IN IT TO STRENGTHEN THE BLOCK". Saw that at the bottom of the add. How does that affect cooling? It is up to $4k now, so maybe it isn't as bad as it innitially appeared to be. Still, thats a lot of CI and HP for those thin cylinder walls. short pistons and such a long stroke.

 

Me either

Nascar doesn't use that

You should see their boring/honing machine

It gives you a picture to the millionth of the cylinder wall ridges

Going back up their Saturday I can't wait

 

It's not specified what block they used, just what machine was used to prep it..

 

If it is NOT a tall deck block (like Dart Iron Eagle Tall Deck), the MAXIMUM rod length that you'd be able to use would be 5.7 inch which would be much less than ideal... My engine builder told me that for 4 inch stroke, you need 6 inch rods. He said that with 4.125 stroker you need AT LEAST 6 inch rods, ideally longer in order not to mess up engine dynamics (I'm just passing on what he said - I'm not an expert but he is). He said that the only way to get the correct rod length would be with a tall deck block. I wanted my engine to be built as a 447 cubic inch engine but my builder conviced me that the engine dynamics would be a lot better with shorter stroke and longer rods.. My block comes clearanced for 4.125 inch cranks, so that wouldn't have been an issue.. We went with 4 inch stroke due to improved ratios.. (stroke vs. rod length)
My block is a Dart Iron Eagle block but it's the STANDARD DECK height block..
I really don't understand enough about those details but I trust my builder...

 

I went with the Dart Little M and it's standard deck height too. I think the only reason you went with a 434 was so you could have 7 CI more than me right Olivier? We won't talk about the power difference either...

 

Do you use less stroke or are you using 4.125 bore?

I'm using 4.155 bore and 4.0 inch stroke.. I could've gone with 4.185 bore but then I'd have to have the block sleeved if it would have to be bored again.. 4.185 is the maximum bore recommended by Dart

P.S. my machine shop (not the shop that built my engine but the shop that did the machine work on my 406 rebuild) told me that just by using a racing block (Iron Eagle or Little M) you will get 3 more HP due to added block stiffness... Never heared about that before..

 

Yeah, 4.125 bore, 4" stroke. I seriously considered going 4.185" bore, that would be a 440" right? Figured for 13 ci, not worth the inability to rebuild the block. I probably should have gone 434 though, but oh well. SHould be done this week...I hope.

 

It would be a 440 but you don't want to go to the blocks limit.. If I'd have to have the block bored again, I'd try to go to 4.165 first...
Are you gonna have the 427 dynoed?

 

No, out of money and the engine builder doesn't know how to setup EFI motors without putting a carb on it first. Can't put a carb on my intake because the bolt spacing is odd. So...I'm going to get it running with the Edelbrock ECU and longer duration basemap chip, watching for lean conditions very closely. Then probably trailer it to a guy a few hours from here to tune a Megasquirt ECU after I convert it over. That's the plan for the moment anyway. Why can't I like Carburaters?

 

You can always have it dynoed for RWHP.. Those are actually more useable numbers..

 

This isn't due to anything I know from my own expertise, but when I built my first stroker over 20 years ago I was advised by Lunati (who guided me through all the "engineering") to stay at or above 1.5:1 rod/stroke ratio to avoid excessive side loads in the cylinder and, of course, to make more mid-range to top end power.

That 1.5:1 happens to be the same ratio I believe Olivier's new 434 has (6.0/4.0), as well as my 496 project (6.385/4.25).

If that "rated to 700+" engine does have 5.7 rods with a 4.125 stroke, it's only got a 1.38:1 ratio.

 

Now that you've said it, I remember what my builder said.. He was also talking about side load etc..
Why does engine building have to be that complicated

I'll keep my engine building skills to rebuilding and not building.. That stuff is way too complicated...

 

That's what I'm talking about when I say thin cylinder walls and long stroke. It's an accident waiting to happen.

Yeah, I'll probably try to chassis dyno it eventually, that is really what counts anyway I suppose.

 

5.7" to 3.75" for the 383 I built 13-14 years ago. That is right at 1.5:1 as well. Motor still runs great, was just time for an upgrade.

 

The RWHP will give you some idea of the potential ET's that you'll be able to achieve if you take it to the track.. Well, it also depends on gearing and converter.. A tight converter will give you better dyno numbers but worse ET's..

 

Built my first one circa 1980, and I'm still trying to figure them out. Only thing more complicated is... ...no, I probably shouldn't say it.

 

women?

 

Converter? What are you talking about? No converter here! 5-speed will be good for 1 thing beyond cruising...maximum hp on a chassis dyno.

Yeah, I have only built 3-4 motors and of course didn't do the machine work on them anyway. I'm an expert in my own mind at least

 

Ah - forgot that you were running a 5-speed.. You are looking at about a 21 - 28% loss based on accessories.. 21% if you are running open exhaust and all electric accessories.. 28% if you are running all mechanical accessories and full exhaust.. For very restrictive exhaust, you could be looking at up to 35% loss.. Restrictive exhaust is the number one HP killer..

 

Grandsport, your machinist is correct with his statement but he is slightly off with the totals. An aftermarket "race" block, iron, is worth between 20 and 30 Hp over a conventional G.M. casting. This is assuming you "transpose" all the same components over from one to the other.

By the same token an all aluminum block will "lose" up to some 40 HP, again, with all the same pieces. Some will argue it's due to block being
"rigid", we see it as "heat dissipation", or HP leaving through the material. The sleeves in an aluminum SB like Brodix are only about .075" thick per side and cannot "retain" enough heat from the charge.

We've been testing this for some years now with aluminum vs. iron blocks/heads.

Most recently tested a 434" (all aluminum) SB, 11* splayed (Jenkin's) heads, made 950 HP initially, made 975 HP with a simple pushrod change, 3/8" to 7/16". With a substituted "iron" race block AND some 1/2" pushrods we would have seen between 1025 HP and 1040 HP. The 950 to 975 is fact! The 1025/1040 is "guestimated".

Thanks, Gary in N.Y.

P.S. Below here is an excerpt by one Darin Morgan from another forum explaining more about the "material's" used in choosing the platform. In his summation he's comparing "cast" aluminum blocks to "billet" ones, but the part about the cast iron with aluminum is appropriate!

(Quote)
On another note,

A cast iron block with cast iron heads will make more power than any other combination.
A cast iron block with aluminum heads will make less power.
An aluminum block with aluminum heads will make even less power.

There are ways to help out the situation in order to minimize the losses but you will always be down a little with an aluminum block. Billet blocks seem to minimize the losses more than anything else. Thick cylinder walls will help but that limits over all power by limiting valve size so your really screwed coming or going.
_________________
Darin Morgan
R&D-Cylinder Head Dept.
Reher-Morrison Racing Engines
1120 Enterprise Place
Arlington Texas 76001
(End quote)