Hey so when choosing heads for a street car what do you look for. Would a 160cc head be a good choice or is it not much better than stock and maybe one would want to go to 180 or so?
can someone give me the run down on heads 160 vs 180's etc
- Thread starter 90lxwhite
- Start date
Runner volume means almost nothing as far as how a head performs, but unfortunately industry standard is to differentiate cylinder heads by their runner volume. It's just one of those things that causes a lot of confusion but will never change. What makes it even worse is that often it is implied that the bigger the runner volume, the more air the head flows and at a slower velocity, but this is also a fallacy.
To understand why, you need to look at how a cylinder head is designed. Runner volume is the product of runner cross sectional area and runner length. If you try to compare an AFR 185 to a Twisted Wedge 185, it's really apples and oranges, because the TW has a shorter port with a larger cross section. Technically, the TW is a "larger" head, but from a runner volume standpoint, they appear similar.
What makes it even more confusing is that cylinder head manufacturers OFTEN round up or round down runner volume when they name their heads. An AFR 185 likely isn't exactly 185CCs.
So now that I've confused you, the best thing to do is research other people's builds, see what they've used, and see what the outcome is. Dyno performance, drag strip times, etc. Also do some research on cylinder head flow numbers and learn what they mean. learn the different styles of SBF cylinder heads and how they affect performance. How intake and cam come into play. There is an infinite amount of information on this subject, you just gotta dive in and start researching.
To understand why, you need to look at how a cylinder head is designed. Runner volume is the product of runner cross sectional area and runner length. If you try to compare an AFR 185 to a Twisted Wedge 185, it's really apples and oranges, because the TW has a shorter port with a larger cross section. Technically, the TW is a "larger" head, but from a runner volume standpoint, they appear similar.
What makes it even more confusing is that cylinder head manufacturers OFTEN round up or round down runner volume when they name their heads. An AFR 185 likely isn't exactly 185CCs.
So now that I've confused you, the best thing to do is research other people's builds, see what they've used, and see what the outcome is. Dyno performance, drag strip times, etc. Also do some research on cylinder head flow numbers and learn what they mean. learn the different styles of SBF cylinder heads and how they affect performance. How intake and cam come into play. There is an infinite amount of information on this subject, you just gotta dive in and start researching.
Yeah appon researching I read that say a 200cc head would have less velocity than say a 165 and therefore would need a higher reving engine to get any performance out of?? But now I read that you say that is not so..
Easiest way is look at low to mid lift flow numbers. Your "street car" isn't going to spend a lot of time at high lift. And any of the 165-185cc heads will flow tons of air. General rule of thumb about bigger cc heads needing revs for power production is only half right. IMO if you think your going to race it go with the biggest head you can get away with.
What kind of power are you looking to make...and what's your primary useage going to be? Driving conditions, etc?
The Trick Flow Twist Wedge 170 is a pretty good all around head, but there are many others (Ford Racing GT40X, Edelbrock Performer, AFR 165, etc) that sell their own version of "street head" that perform comparably. Cam and intake selection is going to determine how well a head performs as well.
The Trick Flow Twist Wedge 170 is a pretty good all around head, but there are many others (Ford Racing GT40X, Edelbrock Performer, AFR 165, etc) that sell their own version of "street head" that perform comparably. Cam and intake selection is going to determine how well a head performs as well.
Yeah it may make a trip down the track once or twice but its mostly a weekend cruiser type. I doubt that it'll see the redline all that often. As for power I'd like to be around 300 rwhp but I guess I'd settle for 270 or so, right now I'm at a whopping 209. I'm thinking I'm going to give the rhs 160's a try. This will be going on a '95 by the way. I'm ready for the why not buy used afr, tw's etc etc but nah who wants used, you'd still have to put money into used heads which would prob bring you back up to the $1000 mark.
Not necessarily. I got my GT40X heads, fresh from the machine shop decked for trueness, with new guides, new valve seals and a fresh valve job for $700 shipped. Still wrapped in plastic when I got them. There are deals out there, you've just got to look for them.
