That dictates that you want to build a torqey engine. 1500-5500 or so. So then you'd want something like the Comp Cams 268H cam, a good dual plane manifold, and 600 cfm vacuum secondary carb, and good electronic ignition {Duraspark?}.

I think you're on the right track with new heads vs rebuild old heads.

quote:

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Originally posted by 66MustangGTCoupe289:
i never got it. what's so good about GT-40 heads?

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quote:

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Originally posted by MidLifCrisis:
Steve in answer to your reply, I am keeping the trans/torque convert. stock, but I would not be against changing the rear up to no
more than 3.25 or 3.5-1. The rear would be a later improvement if done. I want to keep it suitable/affordable on the highway.
Maybe the question should be rephased as: is the 268H better than the Edelbrock cam? And number 2, as stated in another recent thread, is there enough improvement in the Performer, or should I go the the RPM? Thanks for all answers. Charlie

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Even if you go to the 3.5s you'll still be not revving the engine very high, so the 268H would work great. I've never used the Edelbrock cam before, hopefully others who have used these cams can comment.

Since you are building a low rpm engine, you don't really want the larger ports of the RPM manifold which would make you lose low end torque.

Everyone wants the best of both worlds, performance and economy. They also want their engine to perform like a lion and idle like a kitten. Unfortunately its not possible but the closest you can come is by use of overdrive transmissions and computer controlled EFI. Are you considering either?

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Originally posted by Jeff:
"Unfortunately its not possible but the closest you can come is by use of overdrive transmissions and computer controlled EFI. Are you considering either?

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No, not considering either. I'm strictly old school and I want to retain the "original look". I would love to add an AOD trans, but have other priorities currently. As for EFI, I want to just stick with a carb.
I contacted Edelbrock to get their recommendation and they said the RPM intake was the way to go with the GT-40P heads. With the 268H cam which is recommended by the guys here on the forum as being superior to the Edelbrock cam, I estimate I should hit around 300hp.

In order to make 300HP from 289CID, you need a relatively high RPM, I would guess off the top of my head that you would need to turn 5500 RPM with a peak TQ at 4500 to have an engine with the profile to produce that power. Performer RPM package is about what you are looking at. With that small CID, you would have dismal torque off the line with a stock stall. Also your exhaust ports will need some work, and I would strongly urge you to use headers, long tube headers are more advantageous for a street machine than shorties. I love the Dynomax mufflers.

A 300 HP 289 is definately buildable, but that rear end would mean you need a 3500 stall convertor, and that is hardly streetable in MY definition. There are many folks out there that would disagree with my definition of streetable, but I hate wasting gas just cruising around at 3000 RPM to go 40 MPH.

I had the 279 limited slip dif in my stang and opted to have a big CID motor instead of a 411 rear to give me the low end torque while still retaining that kill em all peak power.

Hi stall TC ~ $300
Close ratio gear set ~$500
3.80 8" gear rebuild ~$350
351W crate motor ~$3500 (add ~$500 for engine swap stuff)
289 rebuild ~$2000 (With perf parts)

It would cost you about double to stuff in a 351 unles you already have one, but the power - oh my - is so sweet.

quote:

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Originally posted by mustangzrule:

Choices, choices. When MEN window shop, this is the stuff we look at.

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I love that quote! My wife hates going to Home Depot with me, because I look at all the potential upgrades while she just sees lumber, paint, and fixtures. She refuses to go to a motorcycle shop wth me.

WVCAT: you're right, there is no substitute for inches, but I can't get over the power a late model 4.6 makes. I'm looking to get less power than a 4.6 from a larger, although antique, mill using modern aftermarket components.

Mustangzrule: thanks for the info. A 351W does make more sense, but the cost factor is near double. Also, maybe I was given a false sense of how appropriate a 289 build-up would be by the dyno data on the Edelbrock website. They show oodles of power with their RPM package of intake, heads, and cam. Also a guy at work just brought in a magazine supplement by HotRod that showed different build-ups and dyno comparisons. It listed a SBF buildup with the RPM intake and XE258 or XE282 cams. I am not familar with them but they showed a flat torque curve for the XE258 and a steep horsepower curve for the XE282. I should have copied the article.
I can't see where 300hp could be extreme when the Hi-po's had 271hp and we have better technology now, especially in better flowing heads. There has got to be a winning combination. I saw MM's thread but I don't want a strip warrior, just a surprisingly quick 35 year old relic.
I appreciate all of the advice and counterpoints. Charlie

Just remember that the old 271hp was the old "gross" measurement and was an advertised number during the h.p. wars.

On the same measurement system a 300hp engine might make 200 hp at the rear wheels. Not exactly a "muscle car".

You can't have both a smooth idle and low (numerically) gears, small displacement and high horse power. If you want that then increase the displacement, ie more cubes.