bence13_33

I am looking at building a 540 this winter. The motor would basically consist of :

Block: Dart Big M
Pistons: Diamond 2618 Aluminum Pistons (10 - 10.5:1 Compression)
Rods: 6.385" 4340 H-Beam SCAT Rods w/ ARP Rod Bolts
Crank: 4.25" Stroke 4340 SCAT

I was looking for opinions on the Dart Big M block vs the Merlin III block. I am looking at running pump gas and want to be in the 650hp-700hp range. I have a pair of Pro Topline aluminum 320cc intake runner heads that are currently on my 468 as well as a Weiand Team G intake and 1050 Dominiator w/ progressive linkage that I was planning on using on the motor. I was seriously considering going with a nice solid roller this time around but worry about the longevity of it on the street.

Any input is greatly appreciated, thanks guys

Jeffs82c3

I bought a short block from shafiroff, dart 540, afr 320, callies crank and rods, 10.5-1 compression,1050 aed carb, dart manifold, howards hydraulic roller cam,specs are, .635 lift on the intake, 640 on the exhaust,290 duration on the intake,296 duration on the exhaust, I'm in the process of measuring for the correct length of the pushrod right now... Jeff

427Hotrod

I don't think you couid NOT make 650-700 HP.

Mine is based on an old Merlin II block and I can vouch for the quality of the metal. Been beating on it for 15 years now. The III is similar except it adds the extra head bolts in the lifter valley like the Dart.

Darts are great too...done a few of them and never an issue.

My first combo ran SRP's and later I used Mahle's. The Mahle's are a lot lighter though and use a thinner ring pack.

You'll have some fun!

JIM

a striper

Having used both Dart and World blocks I like your choice. I like the Dart castings much more.

Syl1953

The Dart Big-m is a tough block, they have a higher nickel content. Not sure ,but I seem to remember they are a bit heavier due to the nickel. I would go dart.

GOSFAST

Common build for us here with those specific heads, the 320 Pro-Topline's, now from RHS. Longest one we have out and running is over 11 years now, not a SINGLE customer issue/complaint. This was on the BB/SD Dart iron block

At 10:1 on the hyd-roller retro platform you will generally see 725 to 750 HP with 700+ (nominal) Ft.Lbs. Torque. These units are cammed near 252* @ .050", .700"+ lift, and are on a 112* LS. This cam is specific to this platform.

If you choose the solid-roller platform with a cam to match I would use Comp's new "bushed" roller lifters (96819B's). Having good service to date with these.

At the time Pro-Topline was going "Chapter 11" we tried to buy up all the available castings we could find. I still have a bunch of the 320's on the shelf ONLY for in-house builds.

Thanks, Gary

P.S. Ditch the Weiand it MAY cost you some serious HP, go with the Edel 2927. Stay with the 4500 Holley.

Jeffs82c3

Also, make sure to get a good oil pan,big blocks with a longer stroke like to sling the oil up and mix with air creating oil starvation...

Jebbysan

I worked at World in L.I. for a spell....and dealt with Dart most everyday when I ran the Speed Shop in Michigan.....
I prefer the Dart because of the casting quality but neither has a distinct advantage......at this level.
Dart is ahead in R and D.....remember...these two companies use to be one.....in the early days...products were very similar....like the Intake Manifold (single plain)....but now that has widened quite a bit.
I would definitely go Dart on the heads......
AFR are very nice....but the Dart has it beat dollar for dollar due to the wet flow technology they have been using.....

And again 427hotrod is correct....it would be very hard to not make 700hp.

I lean toward the 950/1000hp Holley on the street....but Dominators look cool and can be tuned as well.....

I think of the 540 as the 1/4" motor.....1/4inch more bore, 1/4 inch longer rod....1/4 more stroke.....it is practically a giant 454.

Great engines and they last a long time.

Have Fun! Bring $$$$$

Jebby