Tyler, I’m using Crane long-body lifters that work with the factory dog-bone guides and retainer.

No real updates to share... just waiting on some parts to come in. Machine shop is a little slow, too.

Just keeping the thread up-top.

Some updates...

One short block is together. .030 over with factory crank, Eagle rods, and 4.50 SRP pistons that are .012 in the hole. The other block is at the shop getting the same treatment.

I changed direction with the cams. I sold the 500 EFI cams and picked up a set of hydraulic rollers that Rookie had for sale. 235/241 @ 050, 647/647. These will be a better match for my AFR heads vs the 500 EFI cams

Heads... kind of a mess but getting through it. I got a very good deal on them, but finding that they really do need a good amount of work. I’m replacing exhaust seats on both sets, and to clean up the decks, they’ll probably need to shrink down to 112 cc chambers. Ouch. I was hoping that I wouldn’t have to go that far, but they’ve been decked before (one set measures at 114 cc and the other 115cc). Compression will come in between 9.3/9.4 using a .039 gasket. I think we’re still doable with 87/89 at this point, though honestly I’ve contemplated selling these and buying a set of EQs so I could avoid the complexity of closed cooling. Oh well, it’s only money and this is what I love doing. They’re going to be beasts when done.

In other news.... steadily making progress on the Bullet. One engine is wired with the other not too far behind. I’m waiting on some fuel fittings that were backordered to come in and need to wire the ignition boxes. The wiring harnesses for the boxes will done using weather-pack connects so those will
be nice. And the hydraulic steering made it in over Christmas.

I’m not sure my neighbors appreciated having a boatyard on their street... so far no one has complained. That might change when the Bullet gets fired up!

Hope everyone is getting a nice start on the new year.

I wish we lived loser, I would love to learn/watch/help with this project.
Tom B.

What amount of quench are you shooting for? I believe if you focus on that your dynamic compression shouldn't be as much of an issue.

I wish I had seen this thread before your block work was done.
If your squish height (clearance between the piston quench pad and the head) was .036" to .040" you would have no trouble running 87 octane with 9.8:1 CR with a 741 cam.
Having your pistons .012 in the hole pretty much kills your ability to induce enough "quench turbulence" to benefit you unless you run .027" Cometic MLS head gaskets (since you are closed cooling, I would probably go that direction if it were me).
The difference in running .036" squish vs anything over .045" is amazing regarding how it suppresses detonation and allows you to run optimal timing with lower octane fuels. It shocks me how so many machine shops choose to ignore this fact.

Here's what I come up with on your combo.
SRP 4.500 pistons with -3cc dish
112cc heads
4.540 gasket ring diameter
.012 in the hole
.039 gasket thickness
RESULT 9.51:1 with .051 quench distance.

Here's what I recommend
.027" Cometic MLS gasket - 4.540 diam.
Same everything as above
RESULT 9.74:1 with .039 quench distance.

You will NOT regret it.
Your cam specs also point towards a need for additional compression vs the 941. It's all a bouncing ball... One thing affects all the others...

There are plenty of guys out there fighting detonation, pulling out timing, searching for higher octane in order to keep their mismatched motors happy.
Then you've got a few really happy guys out there making great power on crappy pump gas with surprising compression ratios. ALL of those guys are running "tight squish" motors.

Mopar 440's in the horrible 1970's smog era were notorious for being knock-happy with traditional hop-up modifications.
They all came from the factory with pistons almost .200 in the holes. Dropping closed-chamber heads on them to bring up compression resulted in pinging knocking turds that required race gas to make it down the road.
The other option was to put big domed pistons in them (still .050 or so in the hole) which provided another knocking pinging turd unless race gas was used.

Past handfull of years, we have been playing with RB Mopars (440's) and setting them all up with .036 squish.
We've got a 509 aluminum head stroker set up at 11.3:1 with a 265 @ 050 cam that we can't make ping with 91 octane - and it's a snappy, responsive, happy beast.
We've got a 440 aluminum head set up at 10.5:1 with a 235 @ 050 cam that is the same story - AND on 91 octane, it PREFERS the timing to be set at 20 initial, 40 total, and 58 vacuum (cruise).
Chevys are the same story - set em up TIGHT and you'll never regret it.

Smokey Yunick devotes an entire page in his book "Power Secrets" to quench. His guideline is .040" for all around performance in a 4" bore engine. Maybe add a few thou for 4.500" bore but sticking to a quench that significantly increases turbulence will greatly help with knock/pinging. I'm sure someone smarter than me will have more to add along with what mcollinstn has stated which is great info as well. Double check your piston rock and if all is well go with the .027" cometic.

Thanks guys. I appreciate all of the advice and guidance.

I had gotten myself all wrapped around the axle regarding the heads and compression that I totally spaced on the fact that quench with the pistons still deep in the hole was going to be an issue. Interestingly, I was thinking about this last night and the light bulb was starting to go off while going through the math and looking at head gaskets.

As it comes together I’ll get it right. I’m not in any hurry to get them done and they will be right and dyno’d properly.

I need to go back and reread everything what was posted.

Again, much much appreciated!

Ordered everything for the bottom end of the second short block this evening.

I’m holding off on head gaskets until I have final measurements. But I have pretty much everything else in-hand.

Cant’t wait to get on the dyno to see what they do!

Any guesses? My buddy Wayne is thinking 580-590. I’m thinking 625.

??

** they’ll be dyno’d with CMI spit tops, etc.