new heads? or new engine?

calpolymustang

Member

Feb 1, 2004

217

0

16

Santa Rosa, CA

May 8, 2008

#1

• May 8, 2008

• #1

The heads on my 289 have to be replaced because one of the valve seats loosened up, and i really dont feel like putting any more money into stock heads.

I'd like to know if you guys recommend i get new heads, or a 5.0 with 50-75k miles. I dont want to change the transmission or the gearing.

Heads would be 58cc, so my compression would drop. Maybe 1.90/1.69. Would I loose much bottom end by having large valves on a small motor? And with this route...i still have just a 289.

The engine would need the balancer/flywheel/waterpump conversion, but what I'm mainly worried about is straining the engine on the freeway (3400rpm seems like a lot for a roller cam).

Any ideas?

 

65ShelbyClone

Founding Member

Sep 9, 2000

4,675

38

119

Antelope Valley, SoCal

May 8, 2008

#2

• May 8, 2008

• #2

Your current cam looks pretty mild. I don't think bigger valves would hurt the low end that much, especially not with a 3500 stall converter. The old school of thought would say that my combo would have terrible low end(single plane, aluminum flywheel, 3.50s, 1.90/1.60 heads, 650 carb, etc), but it is actually very good. It's all in the cam.

I guess it comes down to how cheaply you can get the 5.0 and the matching damper and flexplate versus the cost of whatever heads you are looking at.

 

calpolymustang

Member

Feb 1, 2004

217

0

16

Santa Rosa, CA

May 8, 2008

#3

• May 8, 2008

• #3

Summit has World WindsorJr heads for $820

58cc 1.94/1.60 with 180 runners

With the 5.0, its $150 for flexplate/dampner then additional money for the oil pan and pickup.

 

6

67rcks

Member

Feb 20, 2008

373

0

17

May 9, 2008

#4

• May 9, 2008

• #4

calpolymustang said:

The engine would need the balancer/flywheel/waterpump conversion, but what I'm mainly worried about is straining the engine on the freeway (3400rpm seems like a lot for a roller cam).

Any ideas?

Click to expand...

Maybe I'm missing something but head swap is straightforward and you don't need to make any changes in the lower engine.

 

calpolymustang

Member

Feb 1, 2004

217

0

16

Santa Rosa, CA

May 9, 2008

#5

• May 9, 2008

• #5

Sorry...
With the 5.0 swap... I would need the balancer/flywheel/waterpump conversion, but what I'm mainly worried about is straining the engine on the freeway (3400rpm seems like a lot for a roller cam).

 

D

D.Hearne

New Member

Sep 29, 2000

11,730

6

0

south louisiana

May 9, 2008

#6

• May 9, 2008

• #6

First of all, a roller cammed motor can handle sustained rpms better than a flat tappet can. I don't know what gave you the idea it couldn't. Second, you'd be happier with a milder stall converter. A 3500 stall with what you're running it with is a huge waste. You'd be much happier on the freeway with a something in the 2000 rpm range for stall. I'm running a converter with about this behind my 331 with a Z303 cam (228@.050 duration .587 lift hyd. roller) High rise dual plane intake, same transmission, rear is a 9" with 3.50's, tires are 26.5" tall. I can lightly powerbrake it and lightem up the 295's on demand. Go to a lesser stall converter along with the heads, your wallet will stay full longer.

 

calpolymustang

Member

Feb 1, 2004

217

0

16

Santa Rosa, CA

May 9, 2008

#7

• May 9, 2008

• #7

Thanks for the info.

I'm not looking forward to spending more money on the tranny, and still have the stock-rpm converter. Its in great condition (only a few years old) and has only been on the shelf for a few months. If i dont keep the 3500, ill go back to the stock conveter