Mild 535 inch Hillbilly Prep Nostalgia FE

[CaptCobrajet]

We ran this unit last week.  There was a little more in it, based on past info, but we ran out of time.  Customer was looking for around 800 hp, and 700-ish torque, so when we got past there, we didn't beat it on it too hard.  I had 31° timing in it, but it had a rather large dome by my standards, and a 72 cc chamber.  I usually run much smaller chambers, with just a bump dome, but these heads migrated from another project, so more dome was needed.  I think another 2.5 ° would have shown more power.  I reckon they can test that in the vehicle.

Cubic inch:                 535    (4.345 x 4.500)
Peak Horsepower:    893 at 6500 rpm
Peak Torque:             794 at 5100 rpm
Compression ratio:  13.5:1
Camshaft:                 .700 lift solid roller
Heads:                     BPE   MR Race Pro Port Edelbrock
Manifold:                 BPE modified BBM Tunnel Wedge
Carbs:                       940-ish cfm modified center squirters, inline with factory style linkage.

[Stangman]

Very nice Blair just curious as to what block and what had to be modified for the extra stroke. 900 horse and mild, meaning what camshaft wise.

[475fetoploader]

That’s outstanding!

[e philpott]

Holy moly! 2.5 degrees away from 900 hp with a 700 lift cam ? Am I reading this right ?

[Ghoughton]

You have a knack for getting more with less.....extremely impressive

[CaptCobrajet]

Very nice Blair just curious as to what block and what had to be modified for the extra stroke. 900 horse and mild, meaning what camshaft wise.

It's a BBM iron block.  No mods to the block for 4.500.  I used a 2" rod journal, and you still have to clearance the back four rods so they don't bump the camshaft.  About the same as a 4.375 with a 2.200 crankpin.  I consider it mild because it doesn't have to turn big rpm, it uses stainless valves....no titanium, it has 750# over the nose, .700 lift....an early Drag Week grind like I used in Miller's Cougar several years back, and low timing requirement.  It has compression, but not "end of the scale" compression.  It also doesn't require a bunch of funky heim jointed carb linkage, or Dominator carbs that don't drive very well unless wide open.  It's a fairly basic combo of stuff that works together.

[ToddK]

Wow, that is impressive. But not unexpected from BP.

[KMcCullah]

That's some darn righteous FE steam, Blair. Nice work! The red truck NEEDS a 4.500 arm.

[Joey120373]

Wow, that is pretty impressive stuff. Curious about the crank and rods.

Was this head one that required a modified valve train ( forget what you call it, you install a bar across the head because ) ?

Amazing.

[Stangman]

Excellent explanation easy to understand and it makes the build more impressive. See you at the Beaver

[frnkeore]

Blair, that's outstanding, from a engine that large. 1.67 HP per CI.

Can you tell us the valve size and how much the heads flowed.

[CaptCobrajet]

Blair, that's outstanding, from a engine that large. 1.67 HP per CI.

Can you tell us the valve size and how much the heads flowed.

This particular one has 2.220 intake and 1.680 exhaust valves.  I didn't intend to turn it real high, so I used the small valves to make torque where it wants to reside rpm-wise.  That makes it real snappy with the inches and 13.5 static.  If I was going to the end with it, more cam, a different set of angles on the valvejob, a 2.300 valve with a little more cross section in the port, would all have added up to quite a bit more power.  It also would change the operating range.  This engine will run for years reliably with a 7K shift point and 7300 through the traps.

The heads flow pretty good.  Nevermind the numbers, as it is only one yardstick of several attributes that matter.

[wcbrowning]

What would you estimate output to be if this engine was 10.5:1?

Blair, that's outstanding, from a engine that large. 1.67 HP per CI.

Can you tell us the valve size and how much the heads flowed.

This particular one has 2.220 intake and 1.680 exhaust valves.  I didn't intend to turn it real high, so I used the small valves to make torque where it wants to reside rpm-wise.  That makes it real snappy with the inches and 13.5 static.  If I was going to the end with it, more cam, a different set of angles on the valvejob, a 2.300 valve with a little more cross section in the port, would all have added up to quite a bit more power.  It also would change the operating range.  This engine will run for years reliably with a 7K shift point and 7300 through the traps.

The heads flow pretty good.  Nevermind the numbers, as it is only one yardstick of several attributes that matter.

[CaptCobrajet]

What would you estimate output to be if this engine was 10.5:1?


I suspect it would lose 30-35 hp per point of compression.  Probably around 800 power and 700 torque.  I am thinking real serious about doing one like that for my Hondo Day Cruiser, so I may get to find out.  A dish piston would be more efficient, so losing the dome would work back in the right direction power wise.

[e philpott]

What kind of compression can you get with a flat top ?