This is a newbie question I know but what are the differences in the stages of heads? Say for example PRC's 1.5's and 2.5's. Looking at all the info I can get on a H/C package from them to run on the Torquer II. Differences in power, driveability, etc. etc. This will be on a street and strip car. Thanks all!

 

stage differences are relative, there's no stadardization. within a given company there stage differences are usually related to valve sizing and spring options. also for some a bit more porting is done on the higher stages.

 

What I have seen is. stage 1 some porting with stock springs. Stage 2 mild porting with stiffer springs for higher lift .Stage 3 more porting,bigger valves,double springs up to .650 lift. I would go with Stage 2 or 2.5 with valves springs good to .650 lift to be on the safe side. The Torquer 2 is close to .600 lift.

 

Is there really a difference between the amount of porting and cfm in airflow? Guess I'll go with the 2.5's then.

 

Could be, if you're running a cam big enough to use the extra flow. Otherwise it may just be paying for something you'll never use. If your cam will only be good to .550-.575 then flow past .600 is fairly irrelevant, IMO. Just do your homework and you'll find something that works well. A lot of times, though, stage differences are proprietary jargon specific to a shop.

 

As stated above it just depends on the company your dealing with. We have three stages of heads for most applications. It just a way of allowing you guys to compare apples to apples. Just take a good look at the parts being offered with the heads. Flow sheets are important as well, make sure the heads your buying are flowed and have flow sheets with them.
Other than that it's valve size, quality of the components and the amount port work offered.

 

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