junk yard motor just keeps getting better but now im stuck

[jason-1995fbody]

some of you may know i got a junk yard 350 for my camaro i knew it had a big cam and some other stuff done to it but i was replacing the heads with smaller camber/bigger valve heads but when i pulled the heads i found .060 stamped on the piston 60 over then i compared my new heads intake valve to the original heads and they are actually a little smaller maybe a 16th of an inch the exhuast valve is the same size the new heads definatly have smaller chambers and i have ported them my questions now are should i port my original heads or will the extra compression help more than the slightly larger valve thanks

[Genopsyde]

it's all about the flow. what are the intake runner and exhaust runner sizes of each head?

[Morley]

It all depends on what the difference is between the 2 heads and what your current compression ratio is. If you already have high compression (9.5:1-10:1) and the old heads are say 76cc and the new are 64 or less, then your compression ratio will end up too high for pump gas.

[Genopsyde]

very valid point there, you will have to do the compression math and compensate with head gasket thickness if you want the compression to be the same or close to the same.

[jason-1995fbody]

i dont care about running pump gas im not sure about the runners the research ive dont says they are about the same but my old heads are 72 cc chambers and the new ones are 58 cc chambers also on a side note the valves on the old heads are 1.94/1.5 my new heads 1.85/1.5
but also my dad came over and we were looking at it and he thinks the block has been decked he beleives it will be around 10.5:1 to 11.5:1 compression with the 58cc heads
dont ask ware he came up with this he has been building race cars since befor he could leagaly drive so ill just take his word for it

[Genopsyde]

whatever you compression ratio is now, changing from a 72cc head to a 58cc head will raise it almost by 2.00. 1.87 to be exact.

[jason-1995fbody]

so about 11 to 1 sounds good to me

[Morley]

Originally Posted by jason-1995fbody

so about 11 to 1 sounds good to me

That depends on what it is to begin with. 11:1 would be ok if you were running sequential port FI and used 93 octane. Otherwise you'd better be running 100-110 octane and if it is carbed it better be 110 octane.

[jason-1995fbody]

ok ive decided to spend the money and have the 1.94 valves put in the smaller chamber heads didnt really want to but i think it will be worth it

[Genopsyde]

bigger valves alone will not make a head flow better. you need to get the rest of the work done to accommodate the valve size. port, polish, valve job, port match, etc...

[jason-1995fbody]

Originally Posted by Genopsyde

bigger valves alone will not make a head flow better. you need to get the rest of the work done to accommodate the valve size. port, polish, valve job, port match, etc...

all but the valve job and polish has been done by me spent about 3 weeks grinding away with the help of the old man they look pretty good still amature thow but my budget is small

[Genopsyde]

that's good to hear. not many people know of the little things like that, that can make a significant difference.