360 budget build questions.

Ithink we need to talk.
What you are trying to do, and what I think your are trying to do, may not be the same.
The biggest stumbling block I see is the dual purpose nature of this build. If you optimize for 6250, you will have to be real careful at sealevel.If youre just going down on the occasional trip and are not intending to rip around thats one thing.But if ripping around at sealevel is on the agenda, then we have to keep that in mind.
If you optimize for sealevel, it will be pretty soft at home.So your fun factor will be compromised.
So whats a guy to to? I think you will need to sacrifice something. The header proclaims 360 on a budget.So not knowing the budget, we could be tossing ideas around that just wont fit in your budget.
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The KB107s are flat tops with 5cc eyebrows. Theyre in my combo. They are making 10.7 Scr with 65cc chambers and a +.005 deck height.
Theyre wrong for open chamber heads.Open chamber heads in unmachined state are closer to 70cc or more. Cant get to 11 with those slugs unless you machine the heads(momoney).And you will have a terrible quench clearance.Which may lead to detonation problems down at the bottom of the hill.I am a firm believer in tight quench. Smarter men than me have proposed that tight quench helps to avoid or at least delay detonation with high Dcrs and low octane fuels.And that has been proven to be correct in my build.
To that end,you will need domed slugs, and probably have to machine them to fit the chambers. I have an old KB catalog. It lists two pop ups for 360s; The 190s, and the 191s. While either will be better than the 107s, I feel the 191s are the ones you need. They will have to be carefully fitted to the chambers.(not cheap) Piston machining should not be finalized until the cam decision is made, because the intake closing point determines the Scr target.
The cam choice should be on the small side, so that if you decide to go bigger, the Dcr will fall. If you go the other way, The Dcr will rise and you may run into detonation.If you get greedy on the cam size,You may end up with a soft bottom end; not the hot thing for a streeter. If you feel you have a suitable used cam(and i think the 2bbl cam is a bit too small;The duration might work, but the lift is rather weak ), stick it in the block and degree it. Find the point of intake closing in crank degrees, and plug it into the formula.If it falls somewhere between 45* and 55* ABDC, your close.Then manipulate the deck and dome numbers in the formula to arrive at a Static cr that falls between 11 and 11.5. If your cam is closer to 45* then shoot for 11.5. If your cam is closer to 55*, shoot for 11.
So once the the Scr target is established, The piston tops can be machined to set the quench clearance and to provide the chamber volume to arrive at the target
Alternatively, and this is what I would do, you could order a custom cam. One that will do exactly what youre looking for.Find a cam company that grinds for our bigger lifters,call them up,and explain to them your needs. They will grind you THE cam; one that you will never want to change.
I think it would be a good thing if you found a Mopar machine shop.Tell them what you want, and let them handle the details.Do not let them talk you into machining stuff for the sake of machining stuff. Some shops I have come across want to machine everything in sight. Ive had a couple of blocks ruined by improper machine work.With the plans you are making, the only block machine work I would allow is very light cuts to the decks IF they need it.If your new crank is straight and spins nice in the saddles, do not let them line-hone it. If they tell you they have to,before they shave the decks, run. Find a different shop.
And finally there is one other option.Actually there are 2 options. The first and most obvious is turbo charging.And the second is CID. Neither of these is in the budget, unless you can find a guy with a stroker kit for sale. And in fact there is a guy on FABO right now willing to part with one for less than $1100bucks.Member RJK3
With a stroker kit,the crs tend to to be easier to hit with less machining costs.A high Dcr wont be required either because the CID is working for you. 408cid is a lot of cids.
So plug that 4 inch stroke into the formula with say 70cc heads and a 52* intake closing point, and see what comes up. That kit if still available is only a little bit more than what you are at now,dollar wise.
I see RJK3 says his kit is 9.0 SCr with 70cc heads. I plugged the numbers into the formula and with a 52* closing intake,it works out to a Dcr at sealevel of 7.9, and at 6250 its 6.65. So, the pistons leave a bit to be desired, but at 408cid its 16% bigger than the 360, which even at 6250 is plenty of motor.And you should have no problem burning any crappy gas. Its still for sale. Now at $1050.