Holley Speed Demon Carb

MSD Distributor

The original plan was to use an Edelbrock RPM Airgap manifold, but the runners were just so small.

I elected to go with a Victor instead.

The cam degreed in at 105 In centerline

In duration @ .050 measured 238

Ex duration 242

This build was a small block Ford. I used a Dart SHP block 4.155" bore 8.200" deck height.

The stroke was 3.470" for a final CID of 376

As you can see clearances were a shade under 0.002.

The rods being 0.0019" and the mains closer to 0.0017"

The mains were STD whereas the rods were -0.001 undersize

I prefer exactly 0.002" even 0.0025", but I don't like to see them looser than 0.003.

With a straight main bore you can get away with 0.0015", but the use of 0.001 undersize bearing would loosen such a size to 0.0025"

The only way to establish exact clearances is by using -0.010 bearings and grinding the crank undersize to suit.

I only do that when abosultly neseccary, typicaly I can adjust clearances with the bearings, sometimes with half STD and half -0.001"

Based on CID CR Duration and airflow

this 376 will effortless break through the 500Hp mark

Here are the custom made 4032 forged pistons.

3.47 :- 2 + 5.4 - 8.2 = 1.065 needed for the compression height

You see the dish volume being 10.7cc

The combustion chamber is 58cc, I add 1cc for the area above the rings.

The bore is 4.155 stroke 3.47 gasket diameter 4.200 and thickness .040 the piston was up 0.001 the net result was a static compression ratio of 10.81:1 and when taking in the closing point of the intake valve an effective CR of 9.15:1

Jumping ahead in photos shows the crank pressure was 180psi

 


By using an adjustable pushrod checker and dragging the rocker left/right across marker pen line I found I needed a 6.40"  length pushrod to place the rocker .050 the intake side of the centerline.


While adjustable guide plates are a great idea, they take way longer to install.

AFR 195cc Heads

Flow @ .600 lift In 308 CFM Ex 231CFM