I have a head that according to the casting numbers is a high compression 149 head. It was fitted to a 202 and I'm told it has been rebuilt for ULP and LPG. According to what I've been told it also looks like it has been shaved a little, whether to increase compression more or to solve a warp or other problem. Apparently it also has adjustable rockers fitted. I was selling it on ebay but pulled it because I had originally advertised it as a stock 202 head which is what I'd thought it was. I don't know for sure if it ran alright on the 202 but I'm told it did.

My question is, firstly, is the head directly compatible with a 186 red motor? It has the same port layout for inlet and exhaust, but I'm wondering if the compression will be too high for a 186? I don't really understand the benefits of having considerably higher compression so maybe someone can fill me in on this. What is the purpose/function of the adjustable rockers when I thought the engines had hydraulic lifters and didn't need tappets adjusting. It is not in a performance car, I run a 186 in my land rover and it uses LPG mostly. So if it is going to be too much for such an engine, make it harder to start or require other work to make it work, I don't want to fit it.

I guess what I'm wanting to establish is whether it is worth cleaning it up, wrapping it and storing it in case I need a head for mine at some stage, or selling it. And whether a 149 high comp head is worth more or less than a standard head. Any tips what would be a fair asking price for such a thing? Given the cost to rebuild a head surely it is worth something?

Edited by user Thursday, 19 April 2012 5:38:19 PM(UTC)  | Reason: Not specified

Firstly the adjustable rockers were standard on the 149, as they were on all 149, 161, 179, 186 & early 138 heads, so nothing special there. Many engine builders prefer the older rocker gear because they still do need that initial set-up, but not the regular re-setting as solid lifters require. It is easier to do this with the older rockers than on the fixed 173/202 type.

If a 149 head is fitted to a 179, 186 or 202 it will lift the compression well above 10:1, probably around 10.25, even higher if it has been shaved. If it has hardened seats for ULP & LPG as well as the high compression it would suit somebody who was building a dedicated LPG engine. 10+ compression is too high for regular ULP in a street car, but great for LPG which has a higher octane rating.

Dr Terry

You really won't see much benefit in that level of compression unless you build the rest of the motor to suit; valves, port work, cam, fresh bottom end, carburation and exhaust. Sure LPG likes it but compression alone is barely worth the swap.

11/1 is not TOO much for pump fuel streeter but it's right up there. You'd need to go easy on the timing and run 98. I've got 11/1 in my built 202 but it's a weekend warrior style motor, fully built.

All the above info/posts are on the money but i think to answer you directly i wouldn't bother using it but it can't hurt to keep it :)