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I am a big fan of the as cast 305 afr's on a typical 500" and under bbc. they just work, for not a lot of money...
Originally Posted by MILD THUNDER
(Post 4080638)
I like how they proved ovals work better, by putting a modern designed aluminum oval, up against a 1960's designed GM iron rect head. Not to mention the GM iron headed combo was 9.7:1, with a major port mismatch, and the AFR combo was 10.5:1 port matched. HMM, I guess all rectangles suck. I would have like to see them do a back to back, with a 265 OVAL, VS a 305 Rect on that build. I bet the numbers would have been alot closer. Heck, a 308 Summit brand Iron head will walk away from those vintage 088 GM heads. They could have done a little better in trying to compare oval vs rectangle design.
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Originally Posted by motor
(Post 4080646)
I am a big fan of the as cast 305 afr's on a typical 500" and under bbc. they just work
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That's from people that read to much ,instead of building the damn motor .
Originally Posted by MILD THUNDER
(Post 4080648)
You wouldnt think so around these parts. Most say you if you have a Rectangle ported head, its worthless under 7000RPM. :readinghelp:
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Since we are posting magazine article info, I was just reading an old one on the crapper.
Budmans 454 with AFR 265s. 10.5:1 compression. 242/248 110LSA cam. Single plane. (10.5:1 is pushing the limit imo on pump gas in a boat) 3,300 317 506 3,600 361 526 3,900 393 531 4,200 425 543 4,500 455 564 4,800 516 569 5,100 552 566 5,400 582 556 5,700 603 556 6,000 617 540 6,300 622 518 6,600 620 493 Engine Masters 454 stock 454HO crate bottom end with Dart 310 Pro 1. 8.5:1 compression. 236/242 110LSA. Single plane. (this thing will run on 87 octane all day). 3200 287 472 3400 312 483 3600 333 485 3800 352 487 4000 373 489 4200 396 495 4400 422 504 4600 447 511 4800 473 517 5000 493 518 5200 509 514 5400 519 505 5600 524 491 5800 524 475 6000 520 456 Now you may see that the AFR 265 Combo, made 51 ft lbs more, and 98HP more. But, it also had two full points more compression, and a larger camshaft. Id be willing to bet, that you bump that compression on the Dart headed engine up to 10.5:1, the numbers would be real close. Even still, a 8.5:1 454 making 525HP and 518FTlbs, on 87 Octane, is not exactly a turd, and would make someone a nice long lasting marine engine. The 310 Rectangles they used, might not be theoretically the right head for a small, sub 6000RPM, 454 inch engine. But, sometimes ****t just works. :helmet: |
Originally Posted by MILD THUNDER
(Post 4080466)
If the HP peaks at 6500, well then you chose incorrect parts, like camshaft for example. Most marine builds will make peak torque 1000-1200 rpm below peak hp, but not always.
Budman, use the single plane Dart! |
Originally Posted by Rookie
(Post 4080680)
Hey! I resemble that statement!! :) Never popped a TRS until this year. I wonder what changed... 5700RPM!
Budman, use the single plane Dart! I wonder why I snapped TRS like twigs with 600hp. Maybe it was the 5 blades and 5200RPM in a 40' tank ! I should have ran royal purple lube. :party-smiley-004: |
Originally Posted by MILD THUNDER
(Post 4080638)
Heck, a 308 Summit brand Iron head will walk away from those vintage 088 GM heads.
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So...I've been gone for a few hrs. Enough time to have that Dart oval installed. Is it on yet ?
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Originally Posted by SB
(Post 4080716)
So...I've been gone for a few hrs. Enough time to have that Dart oval installed. Is it on yet ?
Don't I have to port match the oval intake to match the "roval" ports on the heads? |
Originally Posted by motor
(Post 4080639)
So you own Dart oval port single plane intake and you are wondering which intake to use :poopoo:..Why don't you put on the one you own and try it .If you aren't satisfied with midrange by an rpm airgap .Gaskets may be expensive .but less so than a new intake...Especially if you are happy with the dart and game over .....
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