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-   -   Question on 496" build (https://www.racingjunk.com/forums/showthread.php?t=24818)

zipper06 07-04-2009 06:15 PM

Question on 496" build
 
I've been contracted to build a 496" motor for a person, originally considered a pump gas but now maybe 12.5 to 1. My question is i have a chance to buy a new set of Dart 308 iron eagles with jessel rockers also new, i also have a chance to buy a set of Brodix 2Plus fully ported, this engine will be running stacks injection on gas. I talked to Dart tech and they tell me the 308's would be perfect, the 345 iron eagles would be too big. The 308's flow 358 and 286 cfm out of the box. I already have the cam it's .725/.725 on 108 lobe ctrs.. Has anyone been down this road before.
It's going into a 2000lb tube chassis Datona, looking to run about 5.50 in the 1/8th.

Zip.

hammertime 07-04-2009 09:57 PM

I think the 345 would be a better choice, 496's can be made to be strong running motors with the right parts and the heads would hold it back if not big enough IMO

My buddy had a 496 with dart 360's on it the last 2 years it ran VERY good for what it was.

tcarda 07-04-2009 10:14 PM

I agree with the Dart tech for the 308s. A friend of mine has a 489 BBC and is making 846 hp on the dyno with his 308s and a Brodix intake manifold. He had a set of 345s last year, but his engine guy said they were too big and go to the 308s which had better velocity for his cubic inch. He did and he picked up quite a bit of hp. His motor is a single 4 gas dominator carb and 13.6 compression.

zipper06 07-04-2009 10:43 PM

Thanks David,
That's what i thought also. This is a low budget motor, but with a good rotator,stock blk., the cam is 271/275 @ .050. The new 308's available come with new Jessels for $1600.00. I didn't talk to Dick Maskin, but one of his shop guys and he said it should make between 750 and 800 hp with this combo. It's 2 7/16" hilborn stacks on gas. The shop tech said don't necessarly look at the flow #'s of the heads but it's velocity that will really create the hp and torque.
I have to admit i really created a monster with the last b/blk i built, 468" with smaller cam and Brodix 2 plus heads on pump gas. I don't know why but it runs 10.50's @ 126mph on pump gas @ 3700lbs plus, on street slicks, with only a .149 60ft.
This motor would definately run 5.50's in the Datona and i put a .668 lift cam in it. The Brodix 2 plus heads only flow 389 ported VS 358 with the iron eagles out of the box.
Am i confused hell yes :oops: that's why i ask the question, i'm totally a sm/blk person, but i know there's no way in hell that a sm/blk will run 10.50's in a 3700lb car on pump gas with a $1000.00 short blk.

Sorry for rambling.

Zip.

PS i thought you were racing tonite, i would have been but it was 100 degrees here and more mosquitoes than you can spray away. I hate bugs :evil:

hammertime 07-05-2009 05:52 AM

I think the brodix head is a lot better head then that dart 308 for sure. If the price is right I would try for them, the motor will thank ya later. I agree 775-800hp isnt out of sight for that motor at all.

I went racing friday night, car slowed up some and smoked when I got out of it at the finish line. I felt I might have a blown intake gasket so came home and pulled it apart and my guess was right.

LuckyDawgRacing 07-05-2009 01:57 PM

1275S-3 found out the hard way. its the alky

hammertime 07-05-2009 02:07 PM


Originally Posted by LuckyDawgRacing
1275S-3 found out the hard way. its the alky

Been there already .. they also did it. I am thinking my root problem is the sniper intakes doesnt have a hole and the intake has to sit there they are oblonged(sp) holes and intake can sit where it wants not where it should.
I think the sniper is being replaced with a 454R as much as I hate to.

zipper06 07-05-2009 02:15 PM

Roll pins 3/16" front and rear to the block, stops side and forward or backward movement 1 front in the valley ctr. and 1 rear in the valley ctr.

PS David you have a PM about the Bordix 2 plus heads

Zip.

Tod74 07-05-2009 02:48 PM


Originally Posted by zipper06
Roll pins 3/16" front and rear to the block, stops side and forward or backward movement 1 front in the valley ctr. and 1 rear in the valley ctr.

PS David you have a PM about the Bordix 2 plus heads

Zip.

That's a great idea. Any advice on how to get it lined up perfect before you drill the holes?

zipper06 07-05-2009 04:46 PM

Set it on without gaskets, it should seat on both intake surfaces and the valley at the same time if there is no major milling of the head intake surfaces. For example if you take a b/blk chevy manifold without gaskets on a stock short deck you can hardly get a .010 feller gauge under any surface. I just did this with a Hilborn stacks injection unit to make sure the injection unit hadn't been modified.

Zip.


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