351W heads on 289 stock engine

sleeperstang · 11-15-2002, 01:00 PM

Does anyone here know if stock 351W heads can go on a 289 stock engine? I know that 351W heads would have bigger head bolts, but as far as compression due to bigger combustion chambers on the 351W. I think 289 heads are open chamber, but I'm not sure if the 351W heads are the same or not, but if they are closed chamber would I face any concerns there, such as needing bigger gasket or anything. Thanks for help!

gofastmercury · 11-15-2002, 10:45 PM

You can get a bolt kit just for this swap.
As far as the comp goes, it would be close to what you have now, both models changed the cc of the chamber, but not alot. smallest 289 is 53ish, while most 351's are 60ish so if anything you'll lose a little comperssion, but not alot. What years are the heads your swapin? Casting numbers would be helpfull too.

66fastback · 11-17-2002, 12:32 PM

this can be a great swap, but not all 351W heads are created equal. Some can be of almost no benifit at all .....the ports and valve sizes on the mid 70's heads are about the same as what you already have. You are also right to assume that there can be an increase in combustion chamber size, which would cause you to lose compression.

The answer has always been to find a pair of 69 or 70 model heads. I'm sure there are other years that are as good, but these used 58 or 60 cc chambers (as gofastmercury pointed out) and had the bigger ports and valves.

The bottom line? these heads probably give you about the same increase as the GT40 iron heads.....20-30 hp. Consider well the difference, I bet GT40 irons won't cost you much more than finding good 351W heads and rebuilding them. I know everyone is talking about the GT40P's, I'm just not sure about headers available for them, as I think there is a problem with the spark plug angle and clearance.

either way you go, good luck. The heads really make a difference you can feel.

Rev · 11-19-2002, 05:44 PM

I used 351W heads for several years on my 289 block with a 302 crank, .030 over, making it a 306. Mine were later (75?) with larger (1.85/1.55) valves. They were professionally pocket ported and gasket matched. They were also milled to give 9.5/1 CR in my engine.

They worked great up to 5500 RPM and made lots of power. The only reason I changed them was to go to TFTW Al. heads. That did give me some extra power, but only about 30-35 HP. And that was with pocket porting/gasket match and 1.7 full roller rockers (old ones are only roller tip 1.6).

I still have these 351W heads with the roller tip rockers if anyone is interested.

Rev

66StangGuy · 11-20-2002, 02:55 PM

how much do you want for the heads and rockers?
how much work would be needed to fit them to my 289.
thanks

Rev · 11-21-2002, 08:35 PM

I would want $350+shipping for them, but only after having them checked over by my machine shop guy to insure no cracks, good valve seal, etc. These are still press-in studs with 1.6 roller tip rail type rockers from Comp Cams. I'm sure these heads are still in perfect shape with only 35,000 miles since they were completely redone. You would need either the inserts from Edelbrock or the special head bolts from ARP to fit the 1/2" holes in the heads to 7/16" threaded holes in the block. Personally, I would go with the new bolts. Get thread sealer also from ARP for the new bolts. Not sure if you will need new push rods or not. I might be able to supply those as well. I have to look to see if I still have them. Of course you would need intake and head gaskets for the installation.

Rev

11-15-2002, 01:00 PM	#1
sleeperstang Registered Member Join Date: Jun 2001 Location: Lynwood, CA, U.S.A. Posts: 82	351W heads on 289 stock engine Does anyone here know if stock 351W heads can go on a 289 stock engine? I know that 351W heads would have bigger head bolts, but as far as compression due to bigger combustion chambers on the 351W. I think 289 heads are open chamber, but I'm not sure if the 351W heads are the same or not, but if they are closed chamber would I face any concerns there, such as needing bigger gasket or anything. Thanks for help! __________________ 65 Mustang Coupe...Comp Cams 262 Xtreme Energy, T-5 conversion, Romac Balancer, 620 Front Springs-4.5 Mid-eye rear springs.......work in progress

11-15-2002, 10:45 PM	#2
gofastmercury Registered Member Join Date: May 2001 Location: calgary alberta canada Posts: 366	You can get a bolt kit just for this swap. As far as the comp goes, it would be close to what you have now, both models changed the cc of the chamber, but not alot. smallest 289 is 53ish, while most 351's are 60ish so if anything you'll lose a little comperssion, but not alot. What years are the heads your swapin? Casting numbers would be helpfull too. __________________ 93LXcopcarSOLD14.3@96 @ 4500ft 2.02 60ft on street tires. my 67 ranchero NOT A 390 ANY MORE! 460! 3.70's cast manifolds, comp cams 262H, performer, 750DP 100K out of 79 F250 NEW(oct20/02)14.58@95mph 2.3 60 ft corrects to:13.86@100 66 merc comet351w, isky roller 600 lift 268/260@.050, vic jr. 700DP, 5000stall, 4.56's c-4, 3400lbs with driver 12.3@110 @ 4000ft 1.69 60 ft corrects to:11.69@115

11-17-2002, 12:32 PM	#3
66fastback Registered Member Join Date: Mar 1999 Location: Dallas, TX Posts: 208	this can be a great swap, but not all 351W heads are created equal. Some can be of almost no benifit at all .....the ports and valve sizes on the mid 70's heads are about the same as what you already have. You are also right to assume that there can be an increase in combustion chamber size, which would cause you to lose compression. The answer has always been to find a pair of 69 or 70 model heads. I'm sure there are other years that are as good, but these used 58 or 60 cc chambers (as gofastmercury pointed out) and had the bigger ports and valves. The bottom line? these heads probably give you about the same increase as the GT40 iron heads.....20-30 hp. Consider well the difference, I bet GT40 irons won't cost you much more than finding good 351W heads and rebuilding them. I know everyone is talking about the GT40P's, I'm just not sure about headers available for them, as I think there is a problem with the spark plug angle and clearance. either way you go, good luck. The heads really make a difference you can feel. __________________ 66 GT Fastback,fuel injected 5.0, 5-speed, cable clutch, JBA's and duals, 3.40 gears and handling mods...just call me "Doc"

11-19-2002, 05:44 PM	#4
Rev Registered Member Join Date: Nov 1998 Location: Houston, Tx. Posts: 3,887	351W heads I used 351W heads for several years on my 289 block with a 302 crank, .030 over, making it a 306. Mine were later (75?) with larger (1.85/1.55) valves. They were professionally pocket ported and gasket matched. They were also milled to give 9.5/1 CR in my engine. They worked great up to 5500 RPM and made lots of power. The only reason I changed them was to go to TFTW Al. heads. That did give me some extra power, but only about 30-35 HP. And that was with pocket porting/gasket match and 1.7 full roller rockers (old ones are only roller tip 1.6). I still have these 351W heads with the roller tip rockers if anyone is interested. Rev __________________ '66 Coupe, 306, 350-375 HP, C-4, 13.07 e.t., 104.8 mph, 1/4 mi. O.B.C. #2 '66 coupe

11-20-2002, 02:55 PM	#5
66StangGuy Registered Member Join Date: Feb 2002 Location: Diamond Bar Posts: 258	how much do you want for the heads and rockers? how much work would be needed to fit them to my 289. thanks __________________ 66 mustang-292-Holley 4160-World Castings Windsor Sr.-Hooker super comp headers-MSD box & Coil.3.55 gears. B&M Z-Gate-Black leather racing seats with 4pt harnes.

11-21-2002, 08:35 PM	#6
Rev Registered Member Join Date: Nov 1998 Location: Houston, Tx. Posts: 3,887	351W heads and rockers I would want $350+shipping for them, but only after having them checked over by my machine shop guy to insure no cracks, good valve seal, etc. These are still press-in studs with 1.6 roller tip rail type rockers from Comp Cams. I'm sure these heads are still in perfect shape with only 35,000 miles since they were completely redone. You would need either the inserts from Edelbrock or the special head bolts from ARP to fit the 1/2" holes in the heads to 7/16" threaded holes in the block. Personally, I would go with the new bolts. Get thread sealer also from ARP for the new bolts. Not sure if you will need new push rods or not. I might be able to supply those as well. I have to look to see if I still have them. Of course you would need intake and head gaskets for the installation. Rev __________________ '66 Coupe, 306, 350-375 HP, C-4, 13.07 e.t., 104.8 mph, 1/4 mi. O.B.C. #2 '66 coupe

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