Dart 320 Race Series Heads

[Trim'd Up]

Anybody know anything about the Dart Race series heads? I can get a brand new set, already CNC ported for a hell of a deal. I understand they are better flowing heads than the Pro-1's correct? What are the differences?

[Griswald]

www.dartheads.com for their complete line. Pay attention to valve train differences.

[Trim'd Up]

I must be missing the valve train differences. I did find the flow numbers and the race series are rated to flow less than the pro-1's.

[Chris]

Flow isn't everything. Port velocities are a huge consideration, as are I/E flow ratios.

[Griswald]

what he said

[Mrhorsepower1]

The Race series heads are a thicker casting than the Pro 1 line. They have thicker decks and more material to them. The air flow numbers will be a bit higher on the CNC ported race heads than "out of the box" Pro 1's . Both are very good heads, and the race series will last longer especially in a salt water application.

[Chris]

This is an exceptionally good resource-

http://users.erols.com/srweiss/tablehdc.htm#BBChevy

Try this- take a look at the AFR 315CNC head. This is one of those "really works well" pieces that delivers amazing results in the 500-550 cid range in NA or mild blown applications. Pay particular attention to how it flows at moderate lifts, it's intake to exhaust flow ratios and to port velocities. If you use this as a benchmark in comparing other heads, you'll begin to see how this 3-dimentsional issue of flow, volume, velocity and ratios actually relates to real-world performance.


It's easy to make BIG numbers on a dyno (peak horsepower) but if you don't have enough midrange, you might not even be able to get on plane. Big ports aren't everything.

[Steve Miklos]

I had Jerry Slalahowsky (spelling) who was w/ Mercury Racing and now is with Competition Products build up a 540 for me. We went with 315 CC AFR's Mahle pistons Callies crank Dart block. I really wanted the old flat tappet cam from a 575 Mercury because I like extended RPM's 6-6.2 K in my single engine Corsa. Jerry convinced me ( I was not an EZ sell) to use a 900 SC solid roller cam and the current lifter from the Mercury 1075's. The only surprise was pedestal rockers really were not ideal so we went with Jesel.

I was not able to dyno the engine but after dressing it with freshwater Cooling and a 995 CFM demon by Rum Runner I must say I am really impressed. The engine idles in gear at 600 RPM and pulls hard to 6K I would estimate 650 HP at 6K RPM. Jerry is great to work with and the pricing was very fair. Few have built as may marine engines as Jerry.
Steve

[Trim'd Up]

I planned on using the AFR's actually, but I came across this set of Darts for nice price. I am going to pick them up monday. Thanks guys. I appreciated the input.