How much horsepower would be added to a GM 350/290 crate if i put E3 spark plugs and high compression pistons?

how many horsepower would be added to a GM 350/290 crate if i put E3 spark plugs and high compression pistonsHow much horsepower would be added to a GM 350/290 crate if i put E3 spark plugs and high compression pistons?The spark plugs would not add any unless you were replacing fouled plugs. The high compression pistons would add about 3% per unit of compression increase. So if you increased the compression from 10 to 1 up to 12 to one you could expect about 18 hp increase. That is if you were able to obtain aircraft gas to run it on as it would need about 104 octane for that compression. All at a cost of about $900 not including labor.How much horsepower would be added to a GM 350/290 crate if i put E3 spark plugs and high compression pistons?The E3 and all other fancy spark plugs are a joke to real performance guys and builders. You WILL NOT gain ANY power with those fancy plugs over a good std plug thats right for the combo.



I have dyno and track tested every spark plug known to man and will tell you right now , I NEVER seen a gain of any type with E3's, split fires, bosch +4's, etc over a std AC Delco, Autolite, NGK spark plug. In fact some combos lost power with those 'fancy' plugs



On my 505 HP dynoed combo, I ran AC Delco R43S plugs, on new combo making 600 HP, I run Autolite plugs, because AC dont make a good plug thats 14mm threads, 3/4%26quot; reach, 5/8%26quot; hex, and non projected tip



Now on the compression

Going from 8.5:1 to 10:1 will gain you about 20-25 HP and about 25 ft lbs torque.



Only prob is when you bump compression up that much,. you will HAVE to change the cam to a slightly larger cam to keep cyl pressure in check so it will run on pump fuel.



If you keep the small cam in it with a now 10:1 compression you wll run into detonation and ping real bad on pump fuel and will be forced to run race fuel. Going to a bigger cam will cure that