New build's foundation: Mexican 302.
I found a mexican block near my parents' home in Ohio for $400. The fella thinks it's still on its original 4.00" bore. I'm worried about the rust, but excited to give it a shot. If that doesn't work out, Michael Bell has one that's already been built for $600.
I also learned that apparently around '74, the mexican blocks added .020" deck height. I'd guess this was a compression drop due to gas era stuff. It would be good for turbo/blower motors on pump gas. But, I'm hoping the block I'm looking at is the earlier version, or that I can find some affordable pistons that will bring compression back to near 11:1, as the extra compression be preferable to me NA, and I dont think it hurts on nitrous.
Would be lovely if the crank and balancer check out too, and then all I need to get are improved rods and pistons.
For those who may find this later, it's hard to beat the info in this thread:
Ok, there have always been people that thought a mexican block was really no better than a stock block. However, there have been folks that...
www.theturboforums.com
And, though the pics aren't showing up for me now, they may be the ones I reposted here:
The Rub: Well, fellas, I've gotten a top end together that I will swap onto a stock or stockish block, probably this winter. My car's running great, and I'm not in a hurry. So, I figured I'd use the opportunity to try to find a budget-friendly upgrade. I know the mexican and older '60s era...
stangnet.com
The cliff's notes on why a mexican block:
- The #1 issue is keeping the main caps from chattering and walking. Girdles don't fix that, and balancing doesn't either. A rotating assy is balanced at TDC and BDC, but at 90*, the weight still has to be contained by the main cap. When you have a thicker cap and webbing, that obviously helps, and mexican blocks have wider and thicker main caps than ANY of the other production ford blocks - pretty similar to the original 1965 era HiPo 289 blocks.
- The early blocks and mexican blocks have blind main bolt holes, reducing the chances of a crack forming, they are slightly thicker under the main cap registers as well.
- head bolt threads of mexican blocks, and the early 289-302 blocks up to '74 or so, are all blind so there is no chance or issues with water leaking, whereas our later model roller blocks are not blind and headbolts must be sealed.
Reasoning specific to my build:
- I have maybe a 150-200k mi stock shortblock it would make sense to drop $1k+ into refreshing when I do the top-emd build, anyways.
- I plan on stepping up to a new combo that I hope will put me right in the danger zone of the accepted 5.0 roller block limit of 500 rwhp.
- I'd rather build another block while mine is still running and getting me to work every day. A motor swap is faster than an engine build.
- Might do better selling my current motor as a package deal when I can confirm it's in good running condition to a potential buyer.
- Already have 2 Dart block projects. Not looking to build another out. Let's keep things cheaper and I'll always be able to find another shortblock if I blow this one up.