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Author Topic:   SBC Iron head shopping, need input
#28
Dirt Maniac

Total posts: 154
posted February 06, 2002 10:09 AM
I'm building a 6" rod 355 for a mod and would like input on iron heads. I have been looking at Dart and World Products. Have not purchased a cam or pistons yet. Any info will help the cause.

istock59
Dirt Freak

Total posts: 237
posted February 06, 2002 11:15 AM
FWIW - I like GM's L31 Vortec head on my 6" rod 355. Makes good, solid power even with IMCA's 350cfm carb rule.

In my opinion, cam selection is CRITICAL with any under-carbed motor, such as mine. How big of a carb can you use?

[This message has been edited by istock59 (edited February 06, 2002).]

sdhnc29
Dirt Freak

Total posts: 467
posted February 06, 2002 10:27 PM
If your looking at aftermarket heads , the Dart Iron Eagle will be dollar for dollar , your best investment .

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Hendren Racing Engines
Rutherfordton , NC
(828)286-0780

#28
Dirt Maniac

Total posts: 154
posted February 07, 2002 12:11 AM
I'm using a BG 750 with alcohol on my current motor.
Hey sdhnc29, what suggestions do you have on cam selection, intake runner size on the Dart Heads, and intake manifolds. I have heard good things about a victor copy that is being sold for about $120, I think Pro Products was the name. I appreciate the input and let me know if you need more info on my end.

sdhnc29
Dirt Freak

Total posts: 467
posted February 07, 2002 12:37 PM
Alky engines like big intake runners !! So I'd use the 230cc Iron Eagles ! With out dyno testing the Victor copy , I'd be scared to try one , there is too much that could be wrong it , and Alky is very sensitive to distribution . Your best would be the 2925 Super Victor . Other than the Dart/Wilson , I think it's the best on the market right now , and I'm not a big fan of Edelbrock components .

As for cam selection , I need to know a little more about you car , track size , and operation RPM range . As with most alky grinds , you will most likely end up with a custom ground cam . Most book cams have too large of split in duration for alky . Let me know some answers to my questions , and I'll give you some numbers to look for .

Steve

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Hendren Racing Engines
Rutherfordton , NC
(828)286-0780

#28
Dirt Maniac

Total posts: 154
posted February 07, 2002 03:59 PM
Steve,
The car is a 3 link, 2450lbs full, IMCA G-60's, running 7000-7200 rpms with 5.67 gear on 3/8 mile paper clip type track that is normally dry slick. I am planning on running a fast 1/4 mile track this year also.
So, does Dart make the best out of the box intake for the 23 degree heads in your opinion? Thanks again for the help.

sdhnc29
Dirt Freak

Total posts: 467
posted February 07, 2002 05:33 PM
I forgot to ask what size engine your running , this head cold is killing me!!! Also , do you want to use a roller or a flat tappet cam ??

With the Iron Eagles on a 355ci , you should look for a cam that is around 258 int/260 ex @ .050" , provided your running a decent compression ratio . The key to alky is exhaust duration . Alky is an extremely slow burning fuel (much slower than gas), and most book type cams will have too much split in duration between intake and exhaust(i.e. , gas type cam) . We found years ago that if you close up the duration when using alky , you will pick up a ton of torque !! This is due to the fact that your keeping the exhaust valve closed longer , thus allowing your slow burning alcohol to complete it's burn cycle . If you pop the exhaust valve too soon .... then you end up blowing all your torque (unburned fuel) out of your exhaust pipes !! A book cam will work for you , but a custom cam with the duration closed up will vastly improve your torque over a book cam ! Most cam grinders will laugh at you when you tell them what you want , most will refuse to grind this type of cam as well . I'll be happy to email some cam specs to you , so you can have something to go by when ordering your cam . I'd suggest using Dave Crower (this is who I use )for your custom cam , he will grind what you want . He also has some book cams that are very close to what you might need . Let me know , and I'll email some spec's to you , I might even be able to give you a few custom grind numbers that we used years ago in California .

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Hendren Racing Engines
Rutherfordton , NC
(828)286-0780

dirtracers
Dirt Full Roller

Total posts: 74
posted February 14, 2002 08:10 PM
nevermind

[This message has been edited by dirtracers (edited February 14, 2002).]

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