# B20 & B18b Cylinder head differences... **URL:** \ **Category:** PittSpeed Automotive\ **Created:** [August 6, 2005, 11:36am UTC](https://forums.speedlife.net/t/b20-b18b-cylinder-head-differences/176154 "2005-08-06T11:36:38Z")\ **Posts on this page:** 10\ **Page:** 1
**Author:** ![imported\_gearhead](https://yyz2.discourse-cdn.com/flex034/user_avatar/forums.speedlife.net/imported_gearhead/32/5957_2.png) [@imported\_gearhead](https://forums.speedlife.net/u/imported_gearhead)\ **Post date:** [August 6, 2005, 11:36am UTC](https://forums.speedlife.net/t/b20-b18b-cylinder-head-differences/176154/1 "2005-08-06T11:36:38Z")
Any? What are they? Too lazy to search honda-tech right now. ---
**Author:** ![ritalin](https://avatars.discourse-cdn.com/v4/letter/r/74df32/32.png) [@ritalin](https://forums.speedlife.net/u/ritalin)\ **Post date:** [August 7, 2005, 4:37am UTC](https://forums.speedlife.net/t/b20-b18b-cylinder-head-differences/176154/2 "2005-08-07T04:37:19Z")
Slight cam differences I think but as for head design they are virtually identical. The last b20 and Ls heads are both p75 heads if you look on the casting. ---
**Author:** ![imported\_gearhead](https://yyz2.discourse-cdn.com/flex034/user_avatar/forums.speedlife.net/imported_gearhead/32/5957_2.png) [@imported\_gearhead](https://forums.speedlife.net/u/imported_gearhead)\ **Post date:** [August 7, 2005, 9:53am UTC](https://forums.speedlife.net/t/b20-b18b-cylinder-head-differences/176154/3 "2005-08-07T09:53:27Z")
Don’t post if you “think”, cawk. only half decent info i’ve found. [http://www.honda-tech.com/zerothread?id=711341](http://www.honda-tech.com/zerothread?id=711341) ---
**Author:** ![Cheeks](https://yyz2.discourse-cdn.com/flex034/user_avatar/forums.speedlife.net/cheeks/32/5930_2.png) [@Cheeks](https://forums.speedlife.net/u/Cheeks)\ **Post date:** [August 7, 2005, 2:51pm UTC](https://forums.speedlife.net/t/b20-b18b-cylinder-head-differences/176154/4 "2005-08-07T14:51:46Z")
The b20 and ls heads physcially are the same the only difference is the cams and the size of the chamber on the head where the valves are. If you would put a b20 head on an ls block it would lower the compression compared to an indentical ls head. ---
**Author:** ![imported\_gearhead](https://yyz2.discourse-cdn.com/flex034/user_avatar/forums.speedlife.net/imported_gearhead/32/5957_2.png) [@imported\_gearhead](https://forums.speedlife.net/u/imported_gearhead)\ **Post date:** [August 7, 2005, 4:10pm UTC](https://forums.speedlife.net/t/b20-b18b-cylinder-head-differences/176154/5 "2005-08-07T16:10:17Z")
So would that mean that running that head could make for a better boost motor? The guy on honda-tech seems semi-credible saying that the intake ports and manifold are better… ---
**Author:** ![rusty240det](https://yyz2.discourse-cdn.com/flex034/user_avatar/forums.speedlife.net/rusty240det/32/5946_2.png) [@rusty240det](https://forums.speedlife.net/u/rusty240det)\ **Post date:** [August 7, 2005, 5:20pm UTC](https://forums.speedlife.net/t/b20-b18b-cylinder-head-differences/176154/6 "2005-08-07T17:20:51Z")
> [@gearhead](#): > > So would that mean that running that head could make for a better boost motor? The guy on honda-tech seems semi-credible saying that the intake ports and manifold are better… from what i remember, when i had both of them here, i noticed no difference. one thing i did notice with the B20 head, is that the combustion chamber was still 81mm, not opened up to 84 mm like one would think they would do. you could see the line from the headgasket running the whole way around the combustion chambers. at least that’s what i remember. ---
**Author:** ![imported\_gearhead](https://yyz2.discourse-cdn.com/flex034/user_avatar/forums.speedlife.net/imported_gearhead/32/5957_2.png) [@imported\_gearhead](https://forums.speedlife.net/u/imported_gearhead)\ **Post date:** [August 8, 2005, 7:35am UTC](https://forums.speedlife.net/t/b20-b18b-cylinder-head-differences/176154/7 "2005-08-08T07:35:57Z")
> [@rusty240det](#): > > from what i remember, when i had both of them here, i noticed no difference. one thing i did notice with the B20 head, is that the combustion chamber was still 81mm, not opened up to 84 mm like one would think they would do. you could see the line from the headgasket running the whole way around the combustion chambers. > > at least that’s what i remember. thats interesting… u’d think the compression would be higher then? :dunno: ---
**Author:** ![system](https://canada1.discourse-cdn.com/flex034/uploads/speedlife/original/2X/b/b7170c8eddc0b95ece6b88172b2f416a08489a45.png) [@system](https://forums.speedlife.net/u/system)\ **Post date:** [August 8, 2005, 11:54am UTC](https://forums.speedlife.net/t/b20-b18b-cylinder-head-differences/176154/8 "2005-08-08T11:54:54Z")
> [@gearhead](#): > > thats interesting… u’d think the compression would be higher then? :dunno: B20 also uses a different piston than the LS because it is 84mm ---
**Author:** ![imported\_gearhead](https://yyz2.discourse-cdn.com/flex034/user_avatar/forums.speedlife.net/imported_gearhead/32/5957_2.png) [@imported\_gearhead](https://forums.speedlife.net/u/imported_gearhead)\ **Post date:** [August 8, 2005, 6:00pm UTC](https://forums.speedlife.net/t/b20-b18b-cylinder-head-differences/176154/9 "2005-08-08T18:00:21Z")
> [@BoostedITR41](#): > > B20 also uses a different piston than the LS because it is 84mm ya, i thougth about that after i posted, but then figured i’d have to figure out what pistons were in each and like do work and stuff…so i said fawk it. thanks for the info though. ---
**Author:** ![ritalin](https://avatars.discourse-cdn.com/v4/letter/r/74df32/32.png) [@ritalin](https://forums.speedlife.net/u/ritalin)\ **Post date:** [August 10, 2005, 2:48am UTC](https://forums.speedlife.net/t/b20-b18b-cylinder-head-differences/176154/10 "2005-08-10T02:48:17Z")
You can use any other b series piston in an Ls except b20. Plus they’re cheap as fuck. I used to have itr’s on one of my old Ls motors.