speaking of SBC blocks

[Dragsinger]

I am beginning the build of a 421 SBC [4.165 x 3.875 that will produce about 725 horse with an upper limit of about 7800 RPM. In this situation. which block would you employ?

[Abbottracingheads]

Dart is redoing some programs on the Litle M block. You can get a raised cam in a little M for no more money. I would do that.

[randy331]

viewtopic.php?f=1&t=52108&start=165

Here's a thread about a 421 I did for our pulling truck. May be some info in it for you.

I used the Dart SHP pro block. I wanted the big block cam journal size and .904 lifter bores it comes with vs the standard shp block. The shp pro block has steel splayed mian caps too vs cast ones on the standard shp block.

This 421 is making a little more power than your saying you'll make, and it has been way over 7800 rpm.
2 seasons in a pulling truck now and still ok.

I knew how my son treats engines so I figured the pro block was worth the extra cost. LOL

Randy

[novafornow]

The SHP block is quite a bit lighter. This is important to some. The little m will take a bigger bore, thus may have an extended life expectancy. If it is true that they are offering a raised cam little M then I would run that one myself. More room in the crankcase, shorter pushrods, seems like a win-win to me.

[406shark]

I just got off the phone with tech at Dart. They are getting close to having the new version of the Little M block. He said they should be available for shipping within the next 2 months?

The version available is the Little M block with billet main caps only.

The cam tunnel is raised .391", and is available in 3 different deck heights.

He said to call and order the block from your machine shop/engine builder. They have part numbers. The part number for the large bore (400ci), stock deck height and 350 main bearing size is 31181215.




Jeff

[randy331]

viewtopic.php?f=1&t=52108&start=165

Here's a thread about a 421 I did for our pulling truck. May be some info in it for you.

I used the Dart SHP pro block. I wanted the big block cam journal size and .904 lifter bores it comes with vs the standard shp block. The shp pro block has steel splayed mian caps too vs cast ones on the standard shp block.

This 421 is making a little more power than your saying you'll make, and it has been way over 7800 rpm.
2 seasons in a pulling truck now and still ok.

I knew how my son treats engines so I figured the pro block was worth the extra cost. LOL

Randy

You used a 3.875 stroke with a BBC cam journal, What was your BC size ???

Standard BBC base circle. I used a 2" rod journal size and had .020" ish rod to cam clearance. Callies ultra HD H beam rods.

Randy

[randy331]

Callies rod part # U16101

Randy

[406shark]

I just got off the phone with tech at Dart. They are getting close to having the new version of the Little M block. He said they should be available for shipping within the next 2 months?

The version available is the Little M block with billet main caps only.

The cam tunnel is raised .391", and is available in 3 different deck heights.

He said to call and order the block from your machine shop/engine builder. They have part numbers. The part number for the large bore (400ci), stock deck height and 350 main bearing size is 31181215.
Jeff

I just looked up the price and its the same at the standard billet cap block. Could not find out any info on lifter bore size or cam tunnel size.

It uses the original oil filter pad as well. Must be standard pan rail as well ??????

He said it was identical to the normal billet cap block... except for the raised cam.

I'm guessing they are attempting to split the difference between the normal Little M block and the Iron Eagle block? I think it's a great feature to add to an already strong block. With so many going for the 3.875" or 4" stroke... it allows for much needed camshaft clearance.




Jeff

[Charliesauto]

You used a 3.875 stroke with a BBC cam journal, What was your BC size ???

Standard BBC base circle. I used a 2" rod journal size and had .020" ish rod to cam clearance. Callies ultra HD H beam rods.

Randy

Callies does not offer a 2.000 journal in the XD design HMMMMM

I believe he is referring to the Ultra H-Beam, not the XD's which as you are stating, are not available in SJ.

[Dragsinger]

The Little M with raised cam sounds like the cat's meow.

[Abbottracingheads]

I am a Dart dealer Larry. Let me know if I can help.

[randy331]

Callies does not offer a 2.000 journal in the XD design HMMMMM

I believe he is referring to the Ultra H-Beam, not the XD's which as you are stating, are not available in SJ.

I build a lot of 421's and I have used the Ultra H beam rods with a standard SB cam journal and using a 421 lobe I still have to use a reduce base circle of 1 inch. That being said there is no way you can use a 3.875 stroke crank and use a BB journal cam.

I don't know what to tell you other than it does have a 3.875 stroke with BBC cam in it,in a Dart shp pro block, and , with the rod part number I posted above. It's tight for sure .020" cam to rod clearance, but it fits and is running fine.

I've used the 2.1" journal comp star rods and 3.75 stroke in a Dart shp pro block too and that set up has more clearance.

It's out of the truck and on an engine stand if you want to stop buy and see for yourself.

Randy

[77cruiser]

These? https://www.cnc-motorsports.com/callies ... 50185.html

Summit has I beams https://www.summitracing.com/parts/cpi-u16101/

[Charliesauto]

Callies does not offer a 2.000 journal in the XD design HMMMMM

I believe he is referring to the Ultra H-Beam, not the XD's which as you are stating, are not available in SJ.

I build a lot of 421's and I have used the Ultra H beam rods with a standard SB cam journal and using a 421 lobe I still have to use a reduce base circle of 1 inch. That being said there is no way you can use a 3.875 stroke crank and use a BB journal cam.

1.868" journal with around.425"-.430" lobe lift should be 1.000" base circle without out any further reduction. More LL than around .430" will be less than 1.00"base circle .

Based on the info you provided, his combo actually adds up. .100" smaller rod journal and .080" larger cam bearing journal.

[steve316]

I have built a few 421 sbc 3.875 stroke; and a couple 427 sbc with 3.940 stroke with 2.00 rods. With a standard base circle cam and comp star h-beam rods that have 1.460 bolts; they clear pan rails and cam. 1 427 had bbc standard base circle cam and one with sbc . the bbc cam I took .040 cut on rod and ended up .038 rod to cam clearance. The pump gas 427 made 631 & the race only one made 824; why would you run a reduced base circle cam?