just a thought.
If aluminum blocks expand a lot, then surely that means the quench gap will expand and subsequent compression will be lowered, as the crank center to head face should lengthen.
Now on a low comp engine this would not have a large effect, but on a 15.1 engine where tolerances are really close then the extra expansion would cause the cylinder to lengthen, hence lowering compression.
It was mentioned that you need to run larger tappet clearances with a solid tappet to assure you keep clearance.
Would those with these measurements be able to do the math on a 15.1 comp ratio and see what it would be reduced to?
Thanks
Joel
 

Todd, is this the engine that Leon built?
Looks great and nice numbers.

In reply to the first post, i can see no benefit in balancing idle with to much accuracy.
1, its common plenum so naturally cylinders will balance from that.
2. You mentioned idle, nothing exciting happens at idle, so no point been to fussy with it.

Have balanced few triple SU carbs on in line 6 engines, using vacume tool, balance idle vac, but more importantly balance the carbs with the throttle cable adjusted tight as the long shaft tends to get a bit of twist so use vac to balance the individual butterfly's.
Also own a nasty motorbike that has 6 carbs running onto individual cylinder intakes, have a 6 Vac gauge cluster for that one, its time consuming and very difficult to access.
i would say most people are more concerned with balancing throttles when linkage is loaded up or wide open to assure max HP.

i had a little bit to do with this  subject,
Except all my experience is with diesels.
Some time a go some of the large cranes i used to maintain ran 3 diesels into a common gear case. The engines i have done this with were V12 Cummins KTA38 all mechanical injection pumped, there was no electrical balancing or load sharing.
These engine all ran ZF 6 speed transmissions fitted with omega drives which are a style of lock up converter that has a shuttle valve mounted to the driven plate, as Rpm increases centrifugal force over comes a light spring and the valve spool activates a converter lock.
We ran greatly differing states of tunes in the 3 engines due to worn parts and availability of correct parts, the diesel injection timing is set on these engines with a offset key way on the each camshaft which effects each bank Intake/Exhaust and injection. There is 2 cams per engine as the pushrods run on the outside of the cylinders. Some times we had engine ready for rebuilds running beside freshly rebuilt units.
I never experienced any issues whilst the engines were under load, we would some times have instances of rattling gears and couplings when the engines were used just above idle with low load. There was allways a lot of pushing and pulling going on between the engines.
I think the most notacble thing was the complete lack of response and lag between throttle commands and rpm. every engine by itself would be quick energetic, but once all coupled up you noticed it became a large elephant instead of the tigers. It was easy to see which engine was leading by the black smoke when been pushed.
I think the spark timing of 2 petrol engines whilst important will not greatly effect the running unless everything else on the engines is also perfectly matched.
This is the reasons why electronic load sharing in diesel power house electricity generation is now so important. Before electronics could automate the load sharing it was common to spend 10 minutes of every hour gently balancing the load between engines and tweaking woodward mechanical governors to control engine surging. All it would take is a slightly worn helm joint on a fuel actuator arm and the whole power house becomes a surging over speeding noise on its way to a guaranteed black out.
I do miss the those times.
Joel
 

Jay,
If that’s a weiand tunnel ram fitted to your adapter?
could you possibly run a tape over it, if you have time.
I am interested in china wall to the carby face.
Total mounted height.
I would love to run that setup, but need to try keep within the laws of my state.
Thanks for all your FE bits and great posts with lots of facts.
Allways a great and interesting read.
Thanks
Joel

Ok,
Rpm FE manifold port matched vs Rpm air gap intake with jays adaptor.
Am I splitting hairs or is there a gain to be had?
Have read Barry’s and Jays books and jays post on his adaptor, the answer is not clear.
I am sure other street builders are interested.
390 stroker
444 cubes 238/ 600 lift cam, roller hyd cam from Barry.
Heads flow 360 intake reworked edelbrocks
Pump gas build.
Thanks for a fantastic forum and great members.
Joel

Brent,
Appreciate input.

110 LSA sounds like fun
112 LSA seems sensible.

What would one expect the differences to be in regards to idle rpm, idle quality, general street manners and lastly horse power.
As this is a street car so that’s a logical order of importance.