gtpvette

iTrader: (2)

I’m in the process of having my motor rebuilt,,, and just ordered TSPs ported 243s with dual springs and the 228R camshaft. I came to this decision after reading the countless posts regarding a good street type cam and I needed new (budget) heads. That said,,, I’ve now been reading about SCR/DCR and I’d like to understand the numbers of the DCR as it seems to be a key indicator for good low-mid power,,, and changing cams now is a whole lot easier than after it’s installed.

So,, does anyone have either the specs on the TSP 228R (228/228, .588"/.588 112 LSA) cam so I might try to figure out the calculator or maybe better yet,,, if you’ve already run the numbers any chance you might pass along your findings????

A couple of other parts, JE 3.905 flattops w -2cc fly cuts,, 64cc heads,, block will be decked but don’t have the exact numbers yet. I haven’t determined exact SCR as of yet (10.4:1??) but I suspect we should be able to raise it a bit if needed.

TSP recommended 112 LSA as the car is rather light 2650#, is a 5 speed but will have AC and I’ll run it. The car is primarily a weekend street toy,,, but there may be a few road race days in it’s future. If you have any suggestions as to what I should be thinking about trying to make this motor right,,, I’m all ears. The hope is a max of about 420 HP with power all the way up the curve. Am I on track??

Thanks!
Fred

pianoprodigy

iTrader: (1)

Fred,

#1 I wouldn't get the ported 243s for your application. The hogged out runners are bad for velocity. I have them on my Z06 with a very similar cam.

#2 Whatever heads you do get, you will probably want them milled to 60 cc chambers to get optimal DCR (8.5-8.7) assuming the deck height is 0.

#3 You will want to get your quench down to between .030 and .040, so use whichever gasket will get you there.

#4 I imagine TSP grinds that cam with 2 degrees of advance. Perhaps someone can confirm that.

I made a few assumptions here, but this will give you an idea.

gtpvette

iTrader: (2)

Pianoprodigy,
Thanks for the info,,, and I’m hoping your assumptions are correct as from what I can tell 8.6:1 should be about right. As for the heads,, I’ve read about the larger intake runners and how they might be better for a larger cam. I would of liked to go with some of the other more expensive heads (AFR!),,, but they’re not in the budget. I am a bit curious about your HP/TQ results on your Z06 as I suspect mine will end up being about the same. Do you think stock 243 castings/ports would be better??

I’m wondering if you think the P/V clearance will be an issue if I go 60CC’s on the heads?? It will be checked,,,, but my motor guy will want to dissemble to fly cut more which means more $$$$$.

I don’t know about quench,,, so I’ll need to read about that.

Thanks again!!!

PREDATOR-Z

With that 228R, 60 cc (4cc mill =~.020) 243 castings will not require more flycutting.
2cc valve reliefs are plenty.
To give you an exemple I'm putting a 232/234 113+0 with a 5.3L heads milled .025 and 2.2 cc valve reliefs. There is plenty space
I say this because the 2.5 stage run the same 2.04 int/1.575 exht valves.
My heads are 59.83 cc

Phil'sC5vette

iTrader: (4)

My results will be on the board next week or so

gtpvette

iTrader: (2)

Well there's good news and bad news. I got my heads but I'm still waiting on the shortblock.

I do have a rather dumb question. I didn't have TSP mill the heads as I wanted to have the final numbers on the deck height. Will they have to be disassabmled to be milled?

Thanks!
Fred

Phil'sC5vette

iTrader: (4)

check out my sig for the 228R and AFRs idle