23 replies to this topic

[stretch tech]

i have a 1038cc stage one kitted with HS4 carb, skimmed block and head, stepped valve seats, 1.75 inch lcb centre exit janspeed single box exhaust hoping for 60ish bhp

standard head?

yup, i did think about getting a 12g940 or similar to put on but i'm on a very tight budget so standard head it was ooh and i have a 3.44 diff rather than 3.1 and slightly shorter tyres

[coopdog]

what about a 12g295 its a straight swap if its skimmed correctly

[stretch tech]

what about a 12g295 its a straight swap if its skimmed correctly

hmm, i might look for one of those i didn't want to get a 12G or similar head as of all the work that is involved in machining them to fit, what do you mean by skimmed correctly ?

[Down&Out]

12g295 is a 1275 head i think, you'd need block pocketing or the valves recessing a bit.

[Sam Walters]

i have a 1038cc stage one kitted with HS4 carb, skimmed block and head, stepped valve seats, 1.75 inch lcb centre exit janspeed single box exhaust hoping for 60ish bhp

45-50 at a push.

[MiniElliott]

12g295 is a 1275 head i think, you'd need block pocketing or the valves recessing a bit.

The 12G295 is a small bore head. 850, 998, 1098
The most common 1275 head is the 12G940.

[Down&Out]

12g295 is a 1275 head i think, you'd need block pocketing or the valves recessing a bit.

The 12G295 is a small bore head. 850, 998, 1098
The most common 1275 head is the 12G940.

My bad, getting the numbers mixed up!

[coopdog]

what about a 12g295 its a straight swap if its skimmed correctly

hmm, i might look for one of those i didn't want to get a 12G or similar head as of all the work that is involved in machining them to fit, what do you mean by skimmed correctly ?

the 12g295 is a straight fit you dont need any machining for them too,

what i mean is the standard 12g295 head has compression chambers of 27cc which would make a 988cc with flat top pistons have 9:3CR much too low,
if you skim it to 24-25cc your CR will be around 10 which is perfect

[stretch tech]

oh right, thanks for that, i'll keep an eye out for one of those speaking of cr, i need help with mine atm - http://www.theminifo...ion-ratio-help/

Rhys