Inliners International Forums General Discussion Hi Performance Help me with my head!

Hi everyone,
Haven't posted in a while, been busy with some other projects while my 250 short block sits in the corner. However, I've recently been sourced for deployment and need to kick start some projects. I'd like to have the engine completely assembled before I leave (August 2015 is the rough timeline so far) and I'm trying to line up what's necessary so as funds come in I can get rolling.

My big thing coming up next is the head. I am looking for some recommendations for what should all be done. I'm assuming lump port and larger valves, but I'm sure I'm missing something as well.

The main goal of the build is volumetric efficiency. Not the most powerful, just trying to increase the efficiency of an older design with newer parts. Of course, I am going for a touch more power than original, but no huge cams here. The short block consists of a balanced 250 rotating assembly with 307 pistons and, IIRC, just over 9:1 compression assuming 72 CC chamber. The cam is pretty mild, “MPG Performance” 273 / 282 @ 0.004 0.461 / 0.491 194 / 204 110, but I would like to design the head with some room to grow should I decide I want to turn up the HP screw. I plan on throttle body injection with an aftermarket intake and headers, possibly even coil per plug ignition but that's more for design fun than performance as a traditional setup would do plenty.

So let me have it, if you would. Tell me how you would build the head, what you recommend.

You might fill us in on what your future upgrades will be in terms of increasing the HP. You can save a lot of money by prepping the head for that end goal rather than a possible re-do later on. That way, you can possibly leave it on the engine at that time and not have the cost of removing it and reworking it added to the other upgrades you plan.

I don't have any plans set in stone, however I know that it's not uncommon to want more!

I don't want to lose my port velocity by going too big, but I'd like to have the ability to go with a larger cam IF I decide to go that route down the road.

Mild enough to be driveable with the current cam, but enough headroom to go larger down the road if so desired. Does that make any sense?

I have no plans to ever build a race engine out of it, but that's not to say I wouldn't go with a little larger cam. If I ever did go crazy on the engine, it would probably end up boosted, but I'm really fighting that urge. It helps I'm building a turbo 3.5L inline 5 on the side as well...

Any advice? Everyone must be workin' on winter projects!

I'm busy.
You mentioned lump ports and larger valves.
1.94/ 1.6
Hardened exh seats
New guides
Pull the rocker studs and convert to screw in 7/16 studs
Port the head
Unshroud the valves
Deck it to raise compression
Viton seals
Shot blast it to make it really clean up after clean and mag check.

I'm sure of that Tlowe. Thanks a ton for the advice!

On a side note, we had discussed trading some cores for your high flow lumps. Let me know if you would still like to do that. I have an entire 230 engine that I could rob parts from.