The heads come in a set of two with stainless valves 1.650-1.575 (oem heads are 1.41-1.275), steel seats, bronze guides, springs and retainers installed. Compatible with oem rockers or roller rockers. They require .400” longer pushrods due to the taller rocker bridge. This modification fixes broken heads and allows for taller/ larger ports.w

These heads were worked off a 3d scan of a stock head. They were then 3d printed to validate a bunch of check points. The stock intake and exhaust will bolt up but an aftermarket intake is best to fully take advantage of the added port flow. We are working on a billet intake and hoping to have it ready as soon as possible. Lets be VERY clear. The oem intakes DO NOT flow enough to allow the heads to make their potential power. The oem efi intake and throttle body (even if its bored out to 33mm) is far too small. It is like a restrictor plate on a nascar engine. The best is an aftermarket, fabricated, or dual carb intake. The oem carbureted intake with an open plenum single 42mm+ mikuni carb is better than the efi setup but still not ideal.

Our 3d printed billet heads hit the mark as far as target flow requirements for theoretical 70+ hp at 5500rpm. Take it with a grain of salt since these are prints but we outflow the stock intake casting by 55% at .500 lift and the stock exhaust by 63% at .450 lift! (Those were our target lifts for flow requirements via our software)

The following measurements may vary slightly, always blueprint your heads by an experienced engine builder before assembling.

We measure the oem combustion chamber to 42cc

These billet heads have a 38cc combustion chamber.

Our billet dished pistons have a 10cc dish and our milled billet pistons have a 3.5cc dish.

Here are some examples of possible compression ratios using a calculator, our billet heads and our billet pistons.

Stock heads, stock length rods, .050 gasket, 10cc dish pistons : 8.5:1

Billet heads, 5.490 rods , .050 gasket, 10cc dish piston: 10:1

Billet heads, 5.555 rods, .050 gasket, 3.5cc dish piston: 11.2:1

Billet heads, 5.555 rods, .020 gasket, 3.5cc dish piston: 12.2:1

The valves billet heads have three locking grooves. Never use the bottom groove (closest to the valve face). The middle groove is the recommended groove to use. The middle groove allows for .510 clearance from the valve guide to the retainer. The middle groove has an installed height of 1.380, the same as our small block vanguards. This is perfect for .450 valve lift. The top groove (furthest from the valve face) allows for .100 more retainer to guide clearance, it also allows for a 1.480 install height. This allows for more lift, it will also however reduce spring pressure. The distance from the valve face to the deck surface is .350’’ (can vary slightly) which is the same as a stock head. If you run milled stock heads chances are you can mill these too to match what you have. Let us know if you want us to mill your heads for you, we offer this for free.

Here are the specs of the valve springs that come standard with the heads:

65 seat pounds @ 1.380 install height

130 pounds @ .500 lift (.800 height)

These heads have 7mm stem valves, they are larger and heavier than stock, more pressure is required than stock heads. These springs on our small blocks are good for 7500 rpm depending on the valve train setup. These billet heads are designed for 5500 rpm, NOT 7500 rpm.

On our flow bench stock heads flow @28’’ :

Intake Exhaust

.100- 39 cfm 37 cfm

.150- 60 cfm 57 cfm

.200- 77 cfm 72 cfm

.250- 86 cfm 78 cfm

.300- 93 cfm 80 cfm

.350- 97 cfm 82 cfm

.400- 100 cfm 84 cfm

.450- 103 cfm 86 cfm

.500- 106 cfm 88 cfm

Our billet heads flow @28’’:

Intake Exhaust

.100- 48 cfm 44 cfm

.150- 71 cfm 64 cfm

.200- 86 cfm 83 cfm

.250- 107 cfm 98 cfm

.300- 122 cfm 115 cfm

.350- 142 cfm 127 cfm

.400- 149 cfm 139 cfm

.450- 155 cfm 147 cfm

.500- 164 cfm 155 cfm

These are “mass produced heads” They haven’t been blue printed for your particular engine, always blueprint your heads for your engine. They are NOT designed to be a bolt on part. They are designed to be as user friendly as possible and as universal as possible but an experienced engine builder is still required to install these. Since they are a “mass produced head” the parts are sold “as is” off the cnc. There are more gains to be had by porting the ports by an experienced cylinder head porter. However do not touch the exhaust unless you are turning past 5500 rpm since it far exceeds the flow requirements for 130% volumetric effeciency for a 60ci engine turning 5500 rpm. The intake however has more potential for gains, however as is it is good to support a theoretical 70hp naturally aspirated at 5500 rpm.

8-12 week wait approx. First batch has been sold

20% discount when ordering 5 sets . Refunded after purchase.