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found the receipt to the engine rebuild the car underwent - i am not familiar with rebuilding an engine - does this build match the original build? - what will the performance be like? thanks

• From September 2008 to April 2009 the original Hemi block was rebuilt by TONY DEPILLO of Dayton OH, as follows:
o Hot tank and boil out block
o 60 over bore and hone
o Custom arias 10.5 pistons and pins
o Recondition and balance rods
o SPS bolts
o Stock crank, balanced and cross-drilled
o 60 off deck surface
o NOS 1970 cam, from 1972
’70 specifications – hydraulic
Lunati cam – Street Hemi 1970 R.L.
111 degrees C.L.
Intake Exhaust
Lift 471 474
Duration 342 348

o Stock hydraulic lifters
o Custom push rods (3/8”)
o Complete head and valve job to unleaded gas
o Double roller chain
o 6qt pan and pick up with windage tray
o New oil pump – high volume
o stall torque converter 2,800

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You would have to do some measurements and calculations to find out your true compression ratio.
Oil pan is incorrect most likely? Camshaft might have more duration than stock.
Sorry but too many unmeasured items to know what exactly you have.
I would guess though even with all these variables that it will run within 2/10 of a stocker but that depends on the tuneup and how efficient that 2800 convertor is.
Just run it at the track to see what it will do.

Sheldon

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You would have to do some measurements and calculations to find out your true compression ratio.
Oil pan is incorrect most likely? Camshaft might have more duration than stock.
Sorry but too many unmeasured items to know what exactly you have.
I would guess though even with all these variables that it will run within 2/10 of a stocker but that depends on the tuneup and how efficient that 2800 convertor is.
Just run it at the track to see what it will do.

Sheldon

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Thanks Sheldon - please forgive my ignorance...but when you say more duration...what exactly does duration do in terms of affecting performance of an engine

Not that it is relevant to this rebuild, but in the papers that came with the car is a receipt from the 1986 Mopar Nationals at National Trail Raceway where the car ran a best of 12.241 at 110.70mph

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With the info given it will idle nice/smooth and run great similar to a stock type build. If you are curious about 1/4 mile times, 13.20-13.50's is likely

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thanks Pacifica - i guess you are all correct...i will have to go the track and see what this engine can do - as per an earlier posting, once in its life it ran a 12.241...but that was an engine rebuild ago (or more?)...

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You would have to do some measurements and calculations to find out your true compression ratio.
Oil pan is incorrect most likely? Camshaft might have more duration than stock.
Sorry but too many unmeasured items to know what exactly you have.
I would guess though even with all these variables that it will run within 2/10 of a stocker but that depends on the tuneup and how efficient that 2800 convertor is.
Just run it at the track to see what it will do.

Sheldon

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Thanks Sheldon - please forgive my ignorance...but when you say more duration...what exactly does duration do in terms of affecting performance of an engine

Not that it is relevant to this rebuild, but in the papers that came with the car is a receipt from the 1986 Mopar Nationals at National Trail Raceway where the car ran a best of 12.241 at 110.70mph

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The engine was rebuilt at least once 22yrs after that , do you know what the specs of the engine were in 1986 ?

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Anyone else a little put off by the cross drilling? Not usually typical of Mopar builders. Not a big deal, but usually people run fully grooved main bearings in MoPars to achieve full time oiling to the rods.

I will claim ignorance in that I've spent very little time wrenching on 426 Hemis, and never have been in the bottom end of one, but I don't believe they ever came with cross drilled cranks, just heat treated/ hardened. This just has me wondering. Anyone?

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The biggest concern I have is compression ratio. Hopefully the custom pistons were made with the .060 deck cut and overbore calculated in, otherwise there may be issues with pump gas. I know Hemi's are more detonation resistant than wedges, but this one could be pushing the envelope for 93 octane and iron heads. Other than that, It sounds like a nice mild street build.

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First of all, congratulations. It sounds like a nice Street Hemi. It should run like a stocker, which isn't too bad. And when you open the hood, WOW! Wall-to-wall engine. It'll get attention.

There's no way to know its octane requirements, but based on the cam selection I would hope it'll run on Premium unleaded gas. There's always race gas and E85 to move up to, but I don't think it'll be necessary.

R.

I thought that name sounded familiar.
http://www.pro-system.com/depilloshow.html

The original Honkin' Hemi, 1st SS/B in the 8's Natl' Record Holder at Bowling Green Ky.

He's on Facebook and LinkedIn, why don't you ask the man himself?

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dog days - that's the guy! - i wonder if he will remember...only one way to find out

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First of all, congratulations. It sounds like a nice Street Hemi. It should run like a stocker, which isn't too bad. And when you open the hood, WOW! Wall-to-wall engine. It'll get attention.

There's no way to know its octane requirements, but based on the cam selection I would hope it'll run on Premium unleaded gas. There's always race gas and E85 to move up to, but I don't think it'll be necessary.

R.

I thought that name sounded familiar.
http://www.pro-system.com/depilloshow.html

The original Honkin' Hemi, 1st SS/B in the 8's Natl' Record Holder at Bowling Green Ky.

He's on Facebook and LinkedIn, why don't you ask the man himself?

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Anyone else a little put off by the cross drilling? Not usually typical of Mopar builders. Not a big deal, but usually people run fully grooved main bearings in MoPars to achieve full time oiling to the rods.

I will claim ignorance in that I've spent very little time wrenching on 426 Hemis, and never have been in the bottom end of one, but I don't believe they ever came with cross drilled cranks, just heat treated/ hardened. This just has me wondering. Anyone?

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thanks GTX Matt - another ignorant question: what exactly does cross drilling the crank do?

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Great info - thanks GTX Matt!

i suspect that is just what the owner wanted ... a cheater-stock build with just enough extra in enough areas that if tuned correctly it will run really strong but will pass for stock Hemi.

i'll be touching base with him to understand the build in '86 when it ran in the 12's...

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Actually with that 2800 and sticky tires, I wouldn't be surprised if it could run deeper into the 12s 4.10s, and maybe a set of headers. It could be an overall pretty well blue printed engine. I'm actually pretty interested to see how it runs. Maybe that low 12 second time slip wasn't too far off from what you've got. Make sure you let us know how she runs. I love 66 Hemi B bodies, is it a Plymouth?

The above post referencing cam duration and octane basically means: Longer duration cams bleed more cylinder pressure. When the piston is on its way up on the compression stroke the intake valve remains open. Longer duration cams which produce higher horsepower numbers hold the valve open longer on the compression stroke. Because the intake charge has intertia it continues to fill the cylinder even though the piston is traveling upwards.

Long duration cams are designed to maximize this ability to fill at higher rpms. At lower rpms they tend to just bleed cylinder pressure because the incoming air charge doesn't have enough inertia to continue filling the cylinder. This is a big part of the reason that big cams produce a radical idle and poor low speed characteristics (but not the only reason, another big reason is the overlap or the time that both the intake and exhaust valve are open at the beginning of the intake stroke).

Anyway, this lowered cylinder pressure helps to fight off detonation, because it makes the engines effective compression ratio (also known as the dynamic ratio) lower.

The typical compression ratio you see measured and advertised is called the static compression ratio.

To take this example to an extreme: Imagine there was no intake valve. The engine would never detonate because the piston would never compress anything because the cylinder would never seal. Even if you had a measured 15:1 static compression ratio, the dynamic compression ratio would be 0. Obviously this engine wouldn't run, but you get the point.