289's compared GT-40P's???

Coolbreeze · 09-08-2001, 11:47 PM

I heard how good the P heads flow but how do they compare to 289's. Would a set of gasket matched(1250-I & 1415-E) 289's with lager valves (1.90- 1.60) work as well as the P's??? I ask because, I already have the 289's and just was wondering if I should sell them and get the P's. I would love to get some Edlebrocks or some similar aluminums but they are way out of the budget range right now.....

------------------
Mike

T-top 86GT in progress......(budget)
Got car for free(no motor/trans or interior) and have a total investment of $ 200 and some labor time.....

**Part list so far** Adjustable 225 hp Compu Car N2O Kit,, Mac long tubes,, 8.8 from Turbo Coupe(auto),, Comp XE 264 cam,, Ported 289 heads,, Crane 1.6 RR's,, BBK 65mm TB,, 4pt rollbar,,

Unit 5302 · 09-09-2001, 02:02 AM

Same link I furnished fiveohpatrol with on his question about ported E7's vs the stock and ported GT-40p's.
http://www.geocities.com/MotorCity/T.../castiron.html

It's really quite suprising how good the p heads really are.

[This message has been edited by Unit 5302 (edited 09-09-2001).]

84LX89GT · 09-10-2001, 03:55 AM

I read an article on Fletch's carbureted Fox mustang site (forget address), but a guy built a 400 horsepower 302 on a budget using 289 heads. Apparently he preferred the lower compression heads used on the 2 barrels, but you can only put in basically the same size intake valves as the GT40-P because the intake valve interferes with the spark plug hole on the old 289 heads if you use 1.90 intake valves. He also did very extensive porting of the 289 heads and got quite a bit of flow out of them.

------------------
previous name: 84stangLX
'84 Mustang 5.0 LX
my LX
'89 Mustang GT
my GT

Dark Knight · 09-10-2001, 07:11 AM

dont forget that you'd need different headers if you switched to the P heads.. keep the 289 heads or maybe look for some WP iron's...

------------------
84 convt,'95 302,AFR's, performer
3.55's, underdrives BBK shorties
stock cam, 1.7's
13.85@102.5
and a '68 stang that WAS nasty ;-)

HotRoddin · 09-10-2001, 05:16 PM

If you want to stick with stock or near stock type heads forget the 289 heads unless you have a set of the old 289 high performance heads (machined spring seats and screw in rocker studs stock) go for the D00E 69-70 351W heads if you cut the thermactor bump out of the exhust port and clean them up they can be made to flow as good as a set of edelbrocks ! and they have 61cc chambers !

HotRoddin · 09-10-2001, 05:35 PM

Got this from an article i read take it for what its worth ?
home ported 289's C6AE casting with stock (1.78/1.45) valves flowed @ .500" 174 cfm intake and 153 cfm exhust
home ported 351 with enlarged valves (1.94/1.60) flowed 211 cfm intake and 177 cfm exhust
stock gt40P's stock (1.85/1.46) valves flowed 196 cfm intake 138 cfm exhust BUT they do have more efficient combustion chambers !
anyway that should give you enough info to get you a little more confused ! lol

Dark Knight · 09-12-2001, 02:33 PM

he said he already had the ported 289 heads...with the larger valves.. they'll flow better than out of the box -P heads, and you wont lose any compression... are they 53cc heads?

------------------
84 convt,'95 302,AFR's, performer
3.55's, underdrives BBK shorties
stock cam, 1.7's
13.85@102.5
and a '68 stang that WAS nasty ;-)

Coolbreeze · 09-12-2001, 10:13 PM

I really don't know the CC's, this is the first time I have delt with 289's. But I do know they are 65--289's.

mustanger82 · 09-13-2001, 12:10 AM

the 289 castings you have have their advantages they are in your posesion they use "normal" sized hedders and they have the smaller combustion chambers which are great for compression they can be ported and flow well but the largest valve you can fit in the 289 head is 1.88 intake and 1.55 exhaust with out modifying your chamber. Modifying your chamber include clearancing the side of the chamber so the valve can make full travel without making contact with the side of the chamber; this takes away material and some valuable compression is lost, secondly they wont flow as well as the the gt-40ps no matter how good the port job. as well the heads need machining to accept any kind of performance rocker. unless you have the 289 hi-po head.
The gt-40 p has many bonuses it has a revised combustion chamber with places the sparkplug closer to the center of the chamber, which gives a better burn, as well as the shape decreases th equench zone reducing the likely hood of dedonation due to combustion temp. secondly the valve placement is better; the 58 cc head allows for the much larger 1.94 int and 1.60 exh valves and the ports are larger as cast and will flow extreamly well after porting prolly in the 240 cfm range for intake and 175 for exhast which is excellent
the heads are more expensive than the cast heads you have. The pedistals are machined to accept roller rocker, and you need special hedder to fit the wider exhast manifold bolt pattern.
In my opinion the gt-40p head is superior but depending on your performance goal the 289 heads my be adequate anywho thats my 2 cents
sean kisch
hardac12@hotmail.com

89 mustang 1977 351w w/1970 61 cc 302 heads with full port and polish job 1.94 int 1.60 exh eagle h beam rods, stock crank, tfs main stud girdle, tfs forged pistons and edlbrock victor portmatched intake tranny and rear end on the way!!!

09-08-2001, 11:47 PM	#1
Coolbreeze Registered Member Join Date: Oct 2000 Location: ~Columbus~GA~31909~ Posts: 156	289's compared GT-40P's??? I heard how good the P heads flow but how do they compare to 289's. Would a set of gasket matched(1250-I & 1415-E) 289's with lager valves (1.90- 1.60) work as well as the P's??? I ask because, I already have the 289's and just was wondering if I should sell them and get the P's. I would love to get some Edlebrocks or some similar aluminums but they are way out of the budget range right now..... ------------------ Mike T-top 86GT in progress......(budget) Got car for free(no motor/trans or interior) and have a total investment of $ 200 and some labor time..... Part list so far Adjustable 225 hp Compu Car N2O Kit,, Mac long tubes,, 8.8 from Turbo Coupe(auto),, Comp XE 264 cam,, Ported 289 heads,, Crane 1.6 RR's,, BBK 65mm TB,, 4pt rollbar,,

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09-09-2001, 02:02 AM	#2
Unit 5302 Registered Member Join Date: May 1999 Posts: 5,246	Same link I furnished fiveohpatrol with on his question about ported E7's vs the stock and ported GT-40p's. http://www.geocities.com/MotorCity/T.../castiron.html It's really quite suprising how good the p heads really are. [This message has been edited by Unit 5302 (edited 09-09-2001).]

09-10-2001, 03:55 AM	#3
84LX89GT Mustangs Join Date: Jul 2000 Posts: 1,938	I read an article on Fletch's carbureted Fox mustang site (forget address), but a guy built a 400 horsepower 302 on a budget using 289 heads. Apparently he preferred the lower compression heads used on the 2 barrels, but you can only put in basically the same size intake valves as the GT40-P because the intake valve interferes with the spark plug hole on the old 289 heads if you use 1.90 intake valves. He also did very extensive porting of the 289 heads and got quite a bit of flow out of them. ------------------ previous name: 84stangLX '84 Mustang 5.0 LX my LX '89 Mustang GT my GT

09-10-2001, 07:11 AM	#4
Dark Knight Registered Member Join Date: Oct 1998 Location: Az Posts: 854	dont forget that you'd need different headers if you switched to the P heads.. keep the 289 heads or maybe look for some WP iron's... ------------------ 84 convt,'95 302,AFR's, performer 3.55's, underdrives BBK shorties stock cam, 1.7's 13.85@102.5 and a '68 stang that WAS nasty ;-)

09-10-2001, 05:16 PM	#5
HotRoddin cranky old man Join Date: Sep 2001 Location: Longview Texas Posts: 683	If you want to stick with stock or near stock type heads forget the 289 heads unless you have a set of the old 289 high performance heads (machined spring seats and screw in rocker studs stock) go for the D00E 69-70 351W heads if you cut the thermactor bump out of the exhust port and clean them up they can be made to flow as good as a set of edelbrocks ! and they have 61cc chambers !

09-10-2001, 05:35 PM	#6
HotRoddin cranky old man Join Date: Sep 2001 Location: Longview Texas Posts: 683	Got this from an article i read take it for what its worth ? home ported 289's C6AE casting with stock (1.78/1.45) valves flowed @ .500" 174 cfm intake and 153 cfm exhust home ported 351 with enlarged valves (1.94/1.60) flowed 211 cfm intake and 177 cfm exhust stock gt40P's stock (1.85/1.46) valves flowed 196 cfm intake 138 cfm exhust BUT they do have more efficient combustion chambers ! anyway that should give you enough info to get you a little more confused ! lol

09-12-2001, 02:33 PM	#7
Dark Knight Registered Member Join Date: Oct 1998 Location: Az Posts: 854	he said he already had the ported 289 heads...with the larger valves.. they'll flow better than out of the box -P heads, and you wont lose any compression... are they 53cc heads? ------------------ 84 convt,'95 302,AFR's, performer 3.55's, underdrives BBK shorties stock cam, 1.7's 13.85@102.5 and a '68 stang that WAS nasty ;-)

09-12-2001, 10:13 PM	#8
Coolbreeze Registered Member Join Date: Oct 2000 Location: ~Columbus~GA~31909~ Posts: 156	I really don't know the CC's, this is the first time I have delt with 289's. But I do know they are 65--289's.

09-13-2001, 12:10 AM	#9
mustanger82 Registered Member Join Date: Jun 2001 Location: chilliwack b.c. canada Posts: 25	the 289 castings you have have their advantages they are in your posesion they use "normal" sized hedders and they have the smaller combustion chambers which are great for compression they can be ported and flow well but the largest valve you can fit in the 289 head is 1.88 intake and 1.55 exhaust with out modifying your chamber. Modifying your chamber include clearancing the side of the chamber so the valve can make full travel without making contact with the side of the chamber; this takes away material and some valuable compression is lost, secondly they wont flow as well as the the gt-40ps no matter how good the port job. as well the heads need machining to accept any kind of performance rocker. unless you have the 289 hi-po head. The gt-40 p has many bonuses it has a revised combustion chamber with places the sparkplug closer to the center of the chamber, which gives a better burn, as well as the shape decreases th equench zone reducing the likely hood of dedonation due to combustion temp. secondly the valve placement is better; the 58 cc head allows for the much larger 1.94 int and 1.60 exh valves and the ports are larger as cast and will flow extreamly well after porting prolly in the 240 cfm range for intake and 175 for exhast which is excellent the heads are more expensive than the cast heads you have. The pedistals are machined to accept roller rocker, and you need special hedder to fit the wider exhast manifold bolt pattern. In my opinion the gt-40p head is superior but depending on your performance goal the 289 heads my be adequate anywho thats my 2 cents sean kisch hardac12@hotmail.com 89 mustang 1977 351w w/1970 61 cc 302 heads with full port and polish job 1.94 int 1.60 exh eagle h beam rods, stock crank, tfs main stud girdle, tfs forged pistons and edlbrock victor portmatched intake tranny and rear end on the way!!!