Quote:
Originally Posted by Tod
Anyway, if I stick with stock size the ports are pretty much restricted by the location of the guides. The only solution would be to be able to drop the guide down about .120, but then I would need to drop the spring seat area down the same amount so that the clip will slide around the guide underneath the seat. That "solution" would compress the spring more, though. That might create a problem. Ideas?
I'll get back about other points being brought up asap.
Tod
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I don't see a problem dropping the guide down - as most of us have to shim the springs about .120 anyway (to get enough spring pressure with high performance cams). The more important aspect of the port is trying to improve the flow path, the floor and the transition into the bowl - lots of improvements can be made there.
If you could design the port to bowl transition area to handle more flow and make it possible to hand modify the tops of the stock guides to blend into the floor and not create a dead spot - that would be great.
Had another sort of wild idea (haven't thought it through), but what if you 'raised the deck' to give you more port volume above the guide? Yes - it would require longer valves - but that is not that big of a deal (just need to source something that works). Pistons wouldn't be a big deal as the long stroke cranks have to move the pin way up anyway - so moving the pin back down would actually be a good thing (not so close or into the ring pack for large strokes). Just thinking out loud here . . .
I highly suggest that you pickup JWLs book on performance modifications - he shows a lot of methods of port rework with the stock block . . . many would be worth thinking about for a new block. Also, there is no reason to not go to about a 1.7" intake valve and a 1.6" exhaust --- though with port improvements in the exhaust side, I believe a 1.5" valve would handle all the flow.
I definitely would not supply the block with a 'factory relief' - this will make it possible for the high-dollar Ardun crowd to use the block . . . and they'd surely be interested in the 3.5" bore.
Keep the ideas flowing gang . . .
D