Looking for advise

I don't recommend so much compression as 13.5 on a long stroke engine! 421, is that for your block? I normally de-stroke 400 engines and turn them up! Do you have a chip rule and what weight and year of car? 1/4 or 3/8 track? I have never been disappointed in a .066 350 against most engines if rules are not so open in cubes! Stroke requires a lot of prep and clearance on rods and cams as well as pans and steam holes in the heads a must! Heads sounds ok for the price! There are better cams now for longer strokes with Asymmetrical usage! Load of weight and gear with length of track should give you a answer!!! You may not have the best block for 421! Seems it needs a newer block with more clearance and stronger bottom end! With all the dwell timing and compression fuel burn goes quickly putting undue stress on the block if loaded heavy and with all the friction and weight factors with added balancers it is not worth the cost for a bit more unless needed!!! Valve size on the heads would be important!!! 1.6 and 2.02?

The valves on those heads 2.08 1.6

High octane requires heat or compression made heat and burns slower with less but I run pump gas with lower compression and run cooler to get more flow and able to burn more and cleaner faster as I up the timing and let it burn to heat up with a greater expanding rate of the colder mixture to make the power! Another reason for shorter stroke is the burn timing factors of fuels! With the gains in weight loss and not having to make compression compared to a 406 it gets close depending on load factors and desired RPMs with less cost involved!

Money factor has always been there! They still have to drive and get the set-up correct and now days most are follow the leader with the same old thing bought things! Make sure your heads are 1.6 friendly and use no valve seals as to starving for oil and wearing guides with added fuel! Use oil restrictors in the rear and stock crank clearances if you want it to live! No need for high volume or pressure pumps if so that rob horses!

I Have good service out of most any parts as I do not stress them in my process of making power! The rod bolts are the thing if you choke it off by too low of an idle when lifting! I drop intake valve spring pressure as to being held tight by vacuum! To each his own 13-1 is too much for me and coated pistons haven't saved anything for me, I bevel my bottom skirts to not shave the oil off on the way down and hold the piston centered as to not touch and cause friction and heat that causes scuffing! Short pistons have to be tighter about .004 clearance but I like .006 on my builds with longer skirts! Pop-ups get in my way of fuel area and limits my burn timing to other fuels or I loose burn stroke and it has to coast too far between cycles! Most engines do!!! More fuel is not the answer unless you can burn all of it by improving burn stroke timing by matching the fuel better! Every engine design is different as you change brands or ratings with 6 choices to choose from on the street at the pumps! The price is right if you have choice of pistons! The last big motor I worked on to win, I had to retard the cam 4 degrees from engine builders specs and unlocked the MSD system and brought the timing down from 34 to 18, went up 4 jet sizes on all 4 corners of that monster Holley, went from 650 gears to a loaded range holding 526 ratio to start this guy winning again in modified with his big money 421! This was 1/4 mile tracks! The old saying about cubes applies to know-how too! I could not change compression or fuel and stroke but I did get his valve numbers closer to my way of thinking! As my dad used to say-- There are more ways to kill a cat than to choke him to death with butter!!! (NO CATS WERE HARMED TRYING TO FIND OUT!), NO BUTTER LOST EITHER!!!---OR MARGERINE!!! Don't worry about the mule, just load the wagon!!! A little old school tech!!!