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Author
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Topic: heads and cam on 289
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streetstang67
Gearhead Posts: 396
From: SC, USA
Registered: Nov 2002
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posted 02-01-2003 11:02 PM
   
I still have a couple of questions about the best heads and cam for a 289 for the money. Especially the heads. I know the comp 270 was suggested on my earlier post...how much horsepower can I expect out of a cam change from stock to that one? Also, would I be better off getting 351 heads (for cheap...out of junkyard) and having them ported and polished and reassembled with new springs(to match the new cam) or buying some roush or gt40 heads or something like that(dont wanna break the bank)? And how much hp would that give me? I dont have a race car or want a race car....I have a "hot street car"  . Keep in mind that my engine is a 289 with an edelbrock performer intake, holley 600, hooker long tubes, and flowmaster duals. Rear gears are going to be a streetable ratio of 3.27:1 or around there. Tranny is a stock c-4 (i dont want to get a cam so big that a new stall converter is needed). It would be cool to be able to run 13.00's all day with slicks, but thats why I'm asking how much hp the heads and cam would be worth. Thanks a lot
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two89w
Gearhead Posts: 230
From: sydney australia
Registered: Sep 2002
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posted 02-02-2003 03:01 AM
u could do the "afr" thing and get 165's
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MidLifCrisis
Gearhead Posts: 323
From: USA
Registered: Oct 2001
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posted 02-02-2003 04:56 PM
Streetstang67:
Life is full of comprimises. I have just recently gone through this decision making process with my '67 convert. I was looking at the GT-40P heads because they had good flow and were also very inexpensive (about $560/pair assembled new). I wanted to keep the retro look, and I didn't want to use headers so I decided against them. Like you, I considered the 1969-1971 351W heads, which were the hot swap in the 1970's and early '80s. They have the same size valves as the GT-40P, and could accept Hi-Po exhaust manifolds for that stock look. I read that milling the heads would lower the larger head chamber volume to keep the same compession ratio.
What it came down to, for me anyway, was my machine shop guy. He felt the heads would require too much milling to get back the compr. ratio. He suggested porting the stock heads, so I went with the stock heads with the GT-40P valves and a port job for about the same price as new GT-40P heads. I was willing to sacrifice a bit of perfomance for the retro image I wanted. As for you, any new aftermarket head will outflow all but maybe a heavily ported factory head. Then you're spending $ on labor instead of new technology.
The less expensive GT-40P heads would require the additional cost of new headers, but the more expensive AFR or Roush heads could possibly use the headers you currently have. Monetarily it would be pretty even. Performance-wise, two89w is offering a good choice. I have read where that the AFR165 heads excel on strong bottom-end street motors and the new Roush/World heads have also gotten excellent write ups.
If you really want 13's in the quarter, I think you will need more rear gear. The guys in the Racing Forum have more experience than me, but I would guess at least a 3.70 or better to drop under 14 seconds.
My guess is you would have approx. 275-300 flywheel horsepower. The Racing Forum guys may have to correct me on this. I hope this helps.
Sorry for the long post, I like to be thorough.  Charlie [This message has been edited by MidLifCrisis (edited 02-02-2003).]
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'69Stang
Gearhead Posts: 205
From: Detroit, MI USA
Registered: Jan 2002
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posted 02-03-2003 11:13 AM
My previous engine was a 302 with GT-40 heads, Performer RPM, 600 Holley DP and a hydraulic cam which spec'd out at 230/235 duration @ .050 and ,510/.515 lift. The combo made approximately 275 RWHP and 285 RWTQ on a mustang dyno. For a fun street combo I would recommend the Roush Windsor Jr. heads (180cc), Weiand Xcellerator intake, Comp cams 270S and a 650 Holley DP (at least). If you tweak it right you should have 300 RWHP. Get a 3.50 gear. The combo will be mellow and out perfrom most performance cars on the street. ------------------
'69 Mustang Fastback, 351C, Holley 950 HP, New Parker Funnelweb intake, ported 4-v quench heads, 10.75:1, UD pulley, windage tray, Top Loader, 3.89 9" rear
------------------------- 12.51 1/4 mile @ 115.89
60 foot time 2.008 (ouch)
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69 Sportsroof
Gearhead Posts: 1421
From: Valley, Alabama, USA
Registered: Mar 2002
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posted 02-03-2003 11:27 AM
Didn't someone say in another thread that you had to have special headers for GT40-P heads due to spark plug hole location?
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69 Sportsroof
Gearhead Posts: 1421
From: Valley, Alabama, USA
Registered: Mar 2002
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posted 02-03-2003 11:39 AM
Found it...https://mustangsandmore.com/ubb/Forum12/HTML/004396.html
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Huskinhano
Journeyman Posts: 51
From: Montvale, NJ.
Registered: Nov 2002
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posted 02-03-2003 06:13 PM
I'm kinda patial to the GT40P head for a lot of reasons. Basically, they flow well...better then any other common production head. They have a very efficient chamber, requiring about 28 degrees total advance and they're CHEAP! For slightly more then rebuilding a set of 30 year old heads, you can have brand new ones. Hot Rod mag did a build up of a 351W. Using basically stock GT40P heads, they made 388 hp.I'm going to be using the P heads on my 66. Here are some pictures of the MAC headers I'm going to use and some other info. BTW, MAC also makes a 2 1/2" manderal bend system to go with these headers! Although the 2 1/2" system is a bit large for a mild street motor. http://www.picturetrail.com/gallery/view?p=999&gid=1619363&uid=716707&members=1
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streetstang67
Gearhead Posts: 396
From: SC, USA
Registered: Nov 2002
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posted 02-03-2003 06:14 PM
http://store.summitracing.com/partdetail.asp?part=31570http://store.summitracing.com/partdetail.asp?part=22529 Whats the difference in these heads? Would they just bolt up? How much hp would they add without any other mods? Thanks a lot what other things would I have to buy (valves, studs.....)? [This message has been edited by streetstang67 (edited 02-03-2003).]
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MidLifCrisis
Gearhead Posts: 323
From: USA
Registered: Oct 2001
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posted 02-03-2003 10:19 PM
quote:
Originally posted by 69 Sportsroof:
Didn't someone say in another thread that you had to have special headers for GT40-P heads due to spark plug hole location?
If I am not mistaken, I believe the exhaust ports are raised as well as having the plug angle moved for better combustion. The ports exit higher on the side of the head, allowing for a straighter flow path out of the combustion chamber. The headers have to be arched to accomodate the plug, and radius the flow of exhaust downward. This is still a head with great flow at a very economical price.streetstang67 as for the World Products heads- they have larger valves than the
GT-40P heads. So they would probably flow more. The only difference I see between the two is that one has 7/16" studs and the other has 3/8" studs. Bigger is better. They seem to need only rockers and maybe pushrods.
You should check out this website:
www.jason.fletcher.net/tech/flowdata/castiron.htm
It is very informative. As for hosepower, a good set of heads is worth at minimum 50hp. More if you use enough cam and induction to take advantage of them. Balancing the system is the key. Charlie
[This message has been edited by MidLifCrisis (edited 02-03-2003).]
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streetstang67
Gearhead Posts: 396
From: SC, USA
Registered: Nov 2002
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posted 02-04-2003 02:51 PM
What could I do to the stock 289 heads that I have now? Porting, polishing, millind, hardening.....? How much of a gain is there to get?
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streetstang67
Gearhead Posts: 396
From: SC, USA
Registered: Nov 2002
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posted 02-05-2003 05:11 PM
What if I learned and did a minor porting and polishing job to my stock 289 heads, and then took them to a machine shop for them to be milled? How much could be milled without causing problems? How much extra hp would that give me?
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