650cfm holley DP
2200rpm stall
Comp Cam FS 270H-10 (.5 int/ex, 110 lobe sep)
3.70/1 gear

It launches with a heavy bog, but still picks up a 14.3 @ 94mph. I was hoping for a little more from it, which getting it tuned should do for me, but other than that does everything sound in check?

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Originally posted by mvierow:
I just wanted to see what you guys though of this combo on my 289..

650cfm holley DP
2200rpm stall
Comp Cam FS 270H-10 (.5 int/ex, 110 lobe sep)
3.70/1 gear

It launches with a heavy bog, but still picks up a 14.3 @ 94mph. I was hoping for a little more from it, which getting it tuned should do for me, but other than that does everything sound in check?

I figure this is a fairly common combo based on what I have read here in the past month. If anyone has something similar to this, post your times so I can relate. Thanks.

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Alex, I am running a MSD billet with 1 blue and 1 red (?) spring I think. I haven't looked in a while. I am also using the 2nd to smallest washer for more advance. I think I'm about 12 degrees inital and ~34 total.

Marcus I don't have heads yet, but I am planning on putting some on when I put my motor back together. Sounds like this forum heavily supports the World products, what is your outlook?

Jas, picking that cam was probably the hardest part of my engine build up. I was concerned with valve clearence, so I chose the 270, but I am definately planning something bigger as soon as I jump on swapping the short block. Probably a hyd roller.

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67 Fastback - Arctic White Pearl paint
351W ,Trick Flow Aluminum Heads, Edelbrock TorkerII, Carter 750 CFM, Comp. Cam 477/510 219/[email protected], Performance Automatic C-4 Trans, 3.55 gears, Front Disc Brakes, 1-1/8" Fr. 3/4" rear sway bars.

The first things I would change are the heads and torque converter. Personally, I like Airflow Research heads. The AFR 165's would be perfect on that engine. WP Jr's get a lot of support here... but don't work with all the headers out there. You'll need to check around, but if you're running Hooker headers, (from their footnotes) you'll need to purchase their expensive Super Comps, the regular Comps won't work. As for other brand headers, I don't know... The spark plug location is what gets you. They moved it, which places the plug right up against the header tube.

AFR heads have the elongated steam hole, which keeps you from having to drill new ones in the head or deck. (different heads and blocks have the steam holes in different locations). AFR also has the PRETTIEST factory CNC porting I've ever seen. It is truly first rate. I've ordered three sets for engines I've built, and have been 100% happy every time. Tell them your engine combination, and they will happily set the heads up with QUALITY hardware, and springs to match your cam, usually at no extra charge. They are a TOP NOTCH company. You just take the heads out of the box, and install them on the engine. You're done! Measure for proper length pushrods (required on any hotrod engine) and you're ready to go! Most WP heads (if purchased complete) come with really CRAPPY hardware. Beware of this if you go that route. You get what you pay for.

The 270H cam is NOT overly small. It measures 224 degrees @ 0.050" and will make the engine want to shift at around 6300 rpm. Unless you have 10:1 compression or so, I wouldn't even think of going any larger... especially with an automatic. A larger cam will only want an even looser converter. You might get by with a 2800rpm stall converter with the current grind, but if you go with something bigger, you'll need around 3500+ stall for a good launch.

The 650DP will be just fine. As has already been recommended, the installation of larger shooters should help.

Install the bushing in the distributer that allows for the LEAST distributer advance. This will allow you to dial in more initial timing. With an MSD Billet, I believe that bushing is 19 degrees. This will allow you to run around 17 degrees of initial (36 total), which will pick up the launch.

The cam on my mustang only measures 236 @ 0.050" on the intake, and easily spins the engine 6800-7000rpm. It doesn't take a lot of cam to spin a good street/strip 302 over 6k rpm. A cam that is too large really kills the low-end and mid-range... especially if the engine doesn't have a really high compression ratio. You NEED this low-end and mid-range to launch the car when using a streetable converter. The 1/4 mile e.t. is made or killed in the first 60ft.

Good Luck!

Mike, I read an article about those heads in a 5.0 mag around a year ago or so and was very impressed. Your the first person I have talked to though that has actually purchased a pair. Do you know if AFR offers them unassembled? I already have matched springs and all the associated hardware, but would need the valves and push rods. Do you know of any articles that describes how to determine proper push rod length?

How about those JBA shorty headers? They originally caught my eye when I noticed they fit a 351W and a 302/289 plus they have a spherical flange which I hear seals better. Anyone using these?

I think I am in same boat Jas, I plan on driving the car frequently so performance on the track is only half of my concern. I think I'll try the different converter and heads for now since the motor and tranny are both out and torn apart, then shoot for tuning once I get everything back together.

quote:

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Originally posted by mvierow:

Mike, I read an article about those heads in a 5.0 mag around a year ago or so and was very impressed. Your the first person I have talked to though that has actually purchased a pair. Do you know if AFR offers them unassembled? I already have matched springs and all the associated hardware, but would need the valves and push rods. Do you know of any articles that describes how to determine proper push rod length?
Final question, what does the difference in converter diameter effect in terms of performance and street-ability?

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As for the AFR heads... I'm sure you can purchase them in any stage of completion. Just make sure there is no confusion, because if you say "Bare" they will probably come unported. Tell them exactly what you already have, and let them know that you want the ported heads with valves. You may even be able to send them your parts for installation. Who knows. But, they should be able to satisfy you. Treat them with respect, they'll treat you nice.
http://www.airflowresearch.com

To check for correct pushrod length, you'll need an adjustable length pushrod and some liteweight 'checking' valve springs. The adjustable pushrods aren't very strong, and can be bent by regular valve springs.

Anyway, with the lite springs and rocker installed, turn the engine over and see where the roller of the rocker rubs on the valve tip. It should roll right in the center, and not move back and forth across the valve tip very far. It should stay centered. Maximum recommended sweep is 0.080". Chances are, it's not centered on the valve tip, and there's too much sweep.

To bring things into 'spec', the pushrod length will need to be adjusted. As the pushrod length is adjusted, the centering and sweep can be improved. When it's as good as it will get, measure the length of pushrod, and you'll know what length to order. Check both intake and exhaust.

On some odd occasions, the intake and exhaust will need different length pushrods, but not usually. They are regularly pretty close. Sometimes off-brand rockers aren't made to the correct specs, which makes the geometry impossible to get perfect. Some Ford heads have even been designed for Chevy rockers... But these are the exceptions.

Valvetrain geometry is of utmost importance. Bad geometry causes all sorts of problems. If the geometry is way off, valve guides won't last any time. But if it's spot-on, a good set of bronze guides will last for years. Bad geometry can also cause a lot of valvetrain noise.

I built a 383 Chevy stroker recently that needed pushrods 1/4" longer than stock! Those guides wouln't have lasted any time!

Check it out!!!

As for converters, the smaller the diameter, the higher the stall speed. Of course some 10" converters will stall higher than others, but the general rule of thumb applies. A good converter isn't usually the cheapest one. I've heard a lot of people say to stay away from GER. Buy quality here.

Good Luck!

quote:

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Originally posted by n2oMike:
To check for correct pushrod length, you'll need an adjustable length pushrod and some liteweight 'checking' valve springs. The adjustable pushrods aren't very strong, and can be bent by regular valve springs

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One addition. A pair of solid lifters is handy for checking the geometry. Hydraulics will often just compress as the engine is turned over, not opening the valve all the way. Just be sure to swap the hydraulics back in before running the engine.

An old hydraulic lifter can also be modified to "solid" status by taking it apart and filling it with something or welding it. These can also be handy for degreeing the cam, if the dial indicator is placed at the valve.

Good Luck!