Building a race motor for open class (autocross and mid size track). Bottom end is a 3A bores out to 83.5mm and compression will be bumped to 12:1 or slightly higher for race gas only. Looking for cylinder head to rework. The usual stuff... P&P, solid lifters, large valves, etc. Work to be done by one of the reputable shops although recommendation would be appreciated. Haven’t decided on fuel delivery; would prefer carbs with ITB as second option. What’s your recommendation as a starting point? Cast code would really help. Thanks much. XsTwin
1st decision is 8 or 16V. If 8V next would be packaging for me. How do you get a decent sized airbox in? Bought a 2L crossflow 8V lump a while back to get the head to build (another..) race motor for my mk1 as there literally is no space down the back of the motor for proper filtration/airbox. Just a thought Jon
An airbox can be a pain, as cylinders influence eachother, fuel meant for say cyl 2 are not neccesarily burnt in that cyl, due spitback and air/fuel mixture being partly swallowed by another cylinder. An open induction or with a foam filter works best … unless its properly develloped 16V - 2.0 head ABF /ACE / 9A … make good power/ torque at a reasonable cost …. and much off the shelf parts to choose from… No need to go crazy on cams and use of hydro profiles & followers are certainly not a limitation…. 7000 - 7500 rpm allow more than decent power
Sorry, left that out. Was looking for 8V but I guess going 16v isn’t out of the question although trying to make a screamer (8k motor) might be more challenging.
In that case i would go for the crossflow 2.0 head But 2E head ( not crossflow) is also a good choice
Hydro followers make proper set up of cam timing 'difficult'. Heavy, sloppy, why would you make a high revving high budget motor with them? Yes, mech is a pain, but once over the (expensive) pain, no issue. Airbox comment was all to do with keeping the combustion air temp low with adequate volume Take note of HPR's comments Jon