After a too-long hibernation, I am back at work on my '68 street legal open-track car. I have a 580" tall-deck Dart block with billet main caps 5.56" bore with a 5.5" crank, flat-top pistons, h-beam rods all Eagle and SRP parts. I have my old heads, Brodix BB1 that have been extensively worked but still only flow 314cfm on the intake. I also have a new comp cams extreme energy solid rollar about .675" lift that I am considering using in it, but it may be a little small to take advantage of newer heads.

Can anyone recommend a head for this combination. I would consider spread port heads, but the cost of the heads plus valve train and intake manifold seems prohibitive. Thanks!

 

Lot’s of good choices for a conventional port head. Here are three options that should compliment your 580:

http://www.airflowresearch.com/pages/357bbc_rh.htm

http://www.brodix.com/BB-3%20XTRA%20Series.html

http://www.bmfracing.com/images/BMFBBC-385.gif

Good luck,

Mark

 

Thanks ML67

Since I need to be conservative on valve lift for durability (thinking about .700 max), I compared lift at .300, .400 & .500., the BMF head flows between 5% to 8% more (assuming they are all testing the same most optimistic way possible). However the BMR 385 port volume is 8% larger than the AFR and 5% larger than the Brodix, so I would have to say it is a toss-up between them although I have never heard of BMF. After reviewing BMF's site, I suspect they are using Dart castings and going from there (not a bad place to start). Does anyone know differently?

 

I believe the CFE BMF heads use Canfield castings. I have no firsthand knowledge of CFE, but they do have a good reputation. They also offer a 350 CNC version.

The CNC Brodix 3-Xtra's look particularly interesting to me. I still think Brodix have the best castings in the business, and with new CNC ports, are now competitive w/ some of the newer designs out there. And Brodix are known to be conservative on their flow figures.

I'm currently running the AFR 335 CNC heads and are very pleased with them. Given your lift limitations, these may actually work well although the larger cross section area of the 357's may be a better compliment to your 580.

Take care,

Mark

 

Some numbers don't seem correct here? But if you are running a 5.500" stroke make certain you have the center counterweights or you'll never keep the crank in the unit. We couldn't get the last 5.500" through the dyno test without "eating" up mains. It was older stroker crank without those weights. Thanks, Gary in N.Y.
P.S. Those big units like 18 degree heads.

 

Probably a typo. A 4.56" bore x 4.5" stroke ~ 588".

 

Ah, I knew someone would catch me shooting from the hip. It's been too long and I hadn't committed the bore to memory. Actual bore size is 4.530". Eagle cranks have center counterweight and are cross drilled, the crank is actually quite nice looking. Much better than some of the off-shore stuff I got a couple of years ago.

I think I would like 18 degree heads, I believe most of those have much smaller heart-shaped combustion chambers, but aren't most of them spread-port, shaft-rocker only? Probably require 18 degree specific pistons as well. I think I sould be able to get anyone of the those three heads (or maybe the 355cc Dart Pro-1s) with CNC ports for about $6,500 assembled. Anyone know who has best prices or a killer deal?

Thanks, Allan

 

Check Mike Lewis Racing out in California. Tell him Jim sent you. He's a great guy and can usually beat most prices on heads. He's sold several sets to friends and they have all been happy.

The BMF's are CNC'd Canfields. I saw a set last week. Pretty nice CNC work and the numbers were confirmed at the shop I was at. They like getting them and reworking them even more. They use the 385 on the street 632's.

There are quite a few choices out there. *IF* you have an excellent serious porter you can beat the CNC stuff....but it takes a good one. The CNC stuff will get you 95% maybe which is very good out of the box and for the price.

For you open track car, I would expect you would decent staying to the smaller side of heads for power out of turns. What rpm range do you live in? A 580" motor is going to have plenty of midrange and bottom end anyway, so you may want to tailor things to make it pull harder up top. Too much instant on power can make it a handful to drive. My particular 540" has become much faster as I killed off low end power and moved power band upwards somewhat. But I play on the street and dragstrip.

You can look at the Dart 'rollover" heads..they flow incredible air after porting, but still use normal valvetrain stuff.

The Big Chief style stuff is going to need .850-1.00+" lift to work as intended. Not really corner burning reliability stuff!

I just saw a 632" street motor make all over 900 Hp on the dyno with a set of CNC Brodix 3Xtras. Great power for an out of the box head. Another 540 I know of was in the 840Hp range with Dart 335's...but he had all the tricks including vacuum pump system etc. I also know of a 598 race motor using AFR 357's and doing very well over the previous 540 and Dart 335's.

If you are looking for power in the 6500-7000 rpm range..I would go for the larger castings..like Brodix 365's or 370's, the AFR 357's etc.

JIM

 

I have a set of Canfield 350cc runners with 2.35 intake valves that flow just over 400, they are ported . On my 496 they made 790hp at 8100rpm, For you motor since its 580 cubes you will be in a much better rpm range and for a head that size. With a .700 lift cam 800+hp should be no problem while being drivable.

 

How about a set of Sonny Lenoard Hemi heads I know way too expensive. Just a thought. They would be killer on that motor

 

It's been awhile since anyone posted to this thread...so, which head did you use?
Also, are there any of these heads that perform this well that do not raise the exhaust port? I have Hookers' with side pipes and I think raised exhaust ports will cause them to strike the bottom of the frame.
The builder wants to use Dart Pro 1's but this raises the ex. ports by 1/2 inch. Any cures or suggestions?

 

No heads yet, I've been working too much and now I am seriously considering selling it as a project because I don't seem to be able to get it done. I've had the car for 20 years. Maybe it is time for a modded Z06, it will probably be faster on the track and certainly break less. Anybody need a 580" short block?

To answer your question about headers, I have Stall sidepipes made for raised port heads. But since I was planning to use a tall-deck, I was thinking of notching the frame rails to use my existing pipes. I am not sure you will find a modern BBC head with standard exhaust ports, so you will be leaving some hp on table, go for the Pro-1s and buy new or modify your existing headers or frame to fit.