I just started working on my first gen 2 Hemi and I would need some advice from all the Hemi experts on this forum.

The engine is an Indy Max gen 2 hemi that is built and set up for drag racing with the following specs: 4.40 x 4.15 bore and stroke (505cid) Indy 426-1 legend heads with 166cc camber and 285cc intake runners. Weiand tunnel ram and two 780cfm E85 carbs.
The camshaft is an older Reed solid roller cam with 286/286 @ 0.050" and 0.674 /0.674 lift and a static compression of 13.3:1 With the intake valve closing at 88 degrees ABDC the dynamic compression is at 6.64:1

My plan is to change the cam, head gasket and intake so I can run it on the street on 98 octane pump gas. Currently the engine has Cometic MLS head gaskets with 0.45" thickness and if I use the same gasket but with 0.120" thickness and a new camshaft with the following specs 263/269 @ 0.050" and 0.675 /0.650 lift the static compression will be 11.06:1 and the dynamic compression will be 8.26:1 with the intake valve closing at 57 degree ABDC.

When I say run it on the street I do not mean idling at 900rpm all day long in heavy traffic.

Please let me know if this is the totally wrong path to go down. Do I just need to bait the bullet and order a new set of custom pistons to get this right?
How does combustion chamber squish work in a hemi chamber? Will I totally ruin the squish ?

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With those heads it's going to be real lazy down low. They aren't the best choice for a street motor.

You might be able to get away with 11.5 or so on a Hemi. You also might be able to mill the pistons to get there then rebalance IF NECESSARY! It'll have better low-end power with the tunnelram. And you may have to use a 'big' cam to bleed cylinder pressure. A 'smaller' cam would make it run better considering the heads. But, I'd consult a 'pro' for a grind with mild lobe rates etc. Nice engine!

I know that this engine is not built with the best selection of parts for a moderate street hemi engine but I got a killer deal on the complete engine.
I'm not interested in a mild street engine and this engine will only be used for shorts blasts around the country roads where i live.
The engine is going into my 1970 Cuda.

11:1 on a Hemi will be just fine but if your looking to reduce compression with a thicker head gasket it may not be worth the money/hassle of getting longer custom pushrods. I have used Racetec in the past and they will most likely be able to make you a custom piston very reasonably and are very easy to deal with. I currently have a 572 with 11:1 and the CNC ported 426-1 with there 268/264 cam and runs fine on the street.

My additional advise, I would buy a quality roller lifter depending on how the lifter bore is configured and also be aware of the oil drain back sealing in the corners of the head gasket/heads, Sometimes can leak with MLS gaskets if the deck and heads are not prepped correctly.

AG

I run 11.6:1 on 93 in my big Hemi with no issues...A Hemi will tolerate a lot more compression than a wedge on pump gas.

One of the biggest liabilities I see is the 285 cc intake ports. It's going to make all its power upstairs.

Aluminum heads will help keep the combustions chambers cool at less than WOT, I would set the total timing at 34 to 36 BTDC and set the distributor up to have between 14 to 20 BTDC at idle RPM. all in by 2000 RPM
You need to remember that the right foot determines how far the throttle blades are when driving the car on the street
How much traction do you have now?
E body with high HP Hemi, even all aluminum motor, have traction issues with serious HP like that motor should make
Hopefully you don't wrap it around a power pole

So you guys see no problem in terms of piston to chamber squish when increasing head gasket thickness? Is a Hemi chamber less sensitive to that compared with a wedge head?

Thanks for sharing you thoughts on this. Could you please share you cam card? Would be interesting to see where your cam is closing the intake valve ABDC.

I may have missed it but have you measured/confirmed compression ratio?

If not I would start there. May need no changes.

With the current set up the static compression is 13.3:1, With the intake valve closing at 88 degrees ABDC the dynamic compression is at 6.64:1. This cam is at 288/288 @.050" so it will be to much for something that will be driven on the streets.

What I'm really searching for is knowledge and opinions on the route of lowering compression with a head gasket change from .045" to.092" thickness. Will this mess up the quench // squish? I know it would on a wedge head, but how does this effect a hemi chamber?

With the new cam that's on 263/269 @.050" 108 LSA and the intake valve closing at 58 degrees ABDC and the .092" head gasket the static compression will be right at 11.69:1 and the dynamic compression will be at 8.55:1

Opinions on this would be much appreciated.

With the current set up the static compression is 13.3:1, With the intake valve closing at 88 degrees ABDC the dynamic compression is at 6.64:1. This cam is at 288/288 @.050" so it will be to much for something that will be driven on the streets.

What I'm really searching for is knowledge and opinions on the route of lowering compression with a head gasket change from .045" to.092" thickness. Will this mess up the quench // squish? I know it would on a wedge head, but how does this effect a hemi chamber?

With the new cam that's on 263/269 @.050" 108 LSA and the intake valve closing at 58 degrees ABDC and the .092" head gasket the static compression will be right at 11.69:1 and the dynamic compression will be at 8.55:1

Opinions on this would be much appreciated.