hey guys i ported and polished a set of 416 305 58cc heads and put them on a few days ago and Im wondering what my compression ratio is i did a compression test i was at 185 psi in each cylinder and Im also running stock dished pistons with thin metal head gasket and a mild cam 465. 465 224 duration but the engine as been rebuilt less than a yr ago and am wanting to run N2o like a 100 shot ... am i going to be safe ? and could some one give a a ball park for hp and 1/4 time ill give all infomation needed ...

i had 882 heads and they cracked on me ....

 

I ran the numbers and you're probably a bit over 10:1 with that combo of parts. The slightly bigger cam is helping to keep your cranking compression/dynamic compression down to a pump gas friendly level.

With nitrous on that combo I would recommend either a timing retard system when you use the bottle or just manually retard the timing about 4* when you're at the track. And, of course, don't ever run lean- make sure your fuel system is up to the task of feeding both carb and nitrous system all the way up to redline under WOT conditions. These are pretty typical safety precautions with nitrous anyway.

Power? No idea. Maybe 325 on motor and a c-note more on the bottle, of course. But I don't know your whole combination. I'm assuming your typical aftermarket dual plane intake with a 4bbl on top, headers and 3" exhaust with decent flowing muffler.

 

stainless valves?

 

all i did to the heads is ported and polished them all the way back the intake runners measures 2 /18 tall and
1 /1/2 wide still has 1.85 stock intake valves and exhaust valves but upgraded springs to 550. new seals and keepers polished exaust ports and cc ... engine spins past 7000 now before the head swap would only go to 6100 very snappy now i dont think i have enough carb now using a 4140 holly 600cfm my demon is about 700 i cant seem to get it to idle right in gear ... and i think i need a bigger radiator i have single core and engine starts to run warm on highway about 220+ my jets are 3 turns out ... running about 8 degrees advance or im not getting enough pressure though my water pump ... when its running i barely see coolent moving thu and i open when hot i rev it up and see some move but other than that im thinking water pump bad ?

 

well engine went kaboom... every rod berring spun and mains were gone... i just rebuilt it in the last few days now i have 230 psi in each cylinder so im thinking thats at least 12:1 i have a .015 compressed head gasket on there i used flat top h345np hypers +6cc with reliefs crome mollyrings powder metal rods are the ones up from a stock rod used summit rod berrings there equivelent to a p style berring used race berrings for mains powermaster 9600 4:40 gear reduction starter barly turns the engine over need the next modle up .. i used the 416 heads fully ported and polished stock valves edlebrock airgap performer intake dual plane speed demon 660 cfm carb ill give dyno results affter the 100 mi shooting for 400hp