willowbilly3
Well-known member
Does anyone know for sure if I can bolt GT40-p heads on my 260? I am mostly concerned that valves won't hit the block. Or any other concerns I haven't thought of. thanks.
sbf question
- Thread starter willowbilly3
- Start date
Valve size is the least of the issues you are about to uncover. Yes, valve to bore clearance is an issue, and you can only bore a Windsor .030 for more clearance, which is not enough for anything. the best way is lay the exact head you are going to use on the actual block, and check. The next problem is the 351 heads had a larger diameter head bolt, and you must get the head bolt conversion kit, or drill and tap your block for the larger bolts. It was once available from Ford, but I'm sure that is long past. An aftermarket source is available I'm sure. The next issue is combustion chamber volume. There are dozens (maybe more) chamber volumes on Windsor engines. This can make a swap impossible even with special pistons. The next problem is there have been several methods of guiding the rocker arms over the years. Early versions used pushrod guided rocker arms, the next version used the rail type guide on the valve stem tips, requiring longer valves, and several other changes. The next version used a positive stop type, the next version used the pedestal type, which is the GT-40 type. The early hi-po engines commonly were converted to pushrod guide plates, and hardened pushrods. All of these swaps, if you can persevere, will need a complete valve train reconfiguration.
After all of this, I have to ask, why? My sons and I go to the road races very often, and even heavily modified 260 Tigers can't keep up with the 4 cyl foreign cars, they just don't have enough power. Even a very heavily modified 260 just doesn't cut it. Just use a 289, and with a QUALIFIED Ford engine builder doing the work, (read, not a backyard hack job utilizing Jegs parts) 500 hp and 9K plus rpm can reliably be obtained, and you will over power most chassis out there.
After all of this, I have to ask, why? My sons and I go to the road races very often, and even heavily modified 260 Tigers can't keep up with the 4 cyl foreign cars, they just don't have enough power. Even a very heavily modified 260 just doesn't cut it. Just use a 289, and with a QUALIFIED Ford engine builder doing the work, (read, not a backyard hack job utilizing Jegs parts) 500 hp and 9K plus rpm can reliably be obtained, and you will over power most chassis out there.
willowbilly3
Well-known member
I don't have the heads and don't want to buy them without researching it some. I know all the different configurations of rocker arms and the readily available info on combustion chamber sizes ect. I am running a 260 now and have another one to rebuild to replace it. I want to keep with the early 5 bolt bell housing that's already in my car. AFAIK, GT40-P heads are NOT the larger 351 head bolts. And both engines do have the same bore spacing, all that. I am 99% sure they will actually bolt on. That's not the issue. And I do realize they will have larger combustion chambers. I will need to research what pistons are available for the 260. I'm not building it to race, could give a hoot if there are 4 bangers that can beat me, there are 4 bangers that can beat most any 50-60 year old V8 design.
I wasn't looking for generic info but someone who has done it or tried to and can say with first hand experience yes it will work or specifically why it won't
I wasn't looking for generic info but someone who has done it or tried to and can say with first hand experience yes it will work or specifically why it won't
Alaska Jim
Well-known member
I am not sure ,but I think you may have to notch the top of the cyl. bore's for valve clearance. I seem to remember something about this with a different head than you are thinking of using, been it has been many years ago. I used to have a 260 in a '63 ranchero with 289 heads , a Sig Erson Hi-Flow 1 cam, a Shelby 289 aluminum intake and 4bbl carb, with a modified C-4. it made plenty of power. not giant H.P. but enough to have fun.
JeffB2
Well-known member
You may want to read these articles: http://www.mre-books.com/interchange/interchange5.html AND http://www.fiveohinfo.com/performance/gt40-gt40p.html I sold basically the same set up as Alaska Jim used to one of my Speed Shop customers back in the 70's for his 260 Falcon Sprint the cam was a custom grind,these engines always can benefit from extra exhaust duration and lift to help them breathe along these lines: http://www.summitracing.com/parts/hrs-mc210021-12/overview/make/ford
willowbilly3
Well-known member
I ca get a set of early 289 heads, which would be an improvement and still have the smaller combustion chambers and the adjustable rockers with the guide style holes for the pushrods and that my be the safest, easiest route. But I was thinking of something with hard seats already in them and I can get a whole 97 Exploder engine for a couple hundred bucks.
I've never built a small block per-se but always heard they favored a dual pattern cam. I'm not going wild with this build, it's just to replace the engine in my rpu, it's getting a little tired, not much oil pressure anymore. I pulled the 80,000 engine from a 63 Fairlane that had been sitting in a field for 15 years so it's done me well, I've rodded the beans out of it for 4 years now. I have a 64 260 to rebuild in my spare time.
The car only weighs 1900#, has a T5 and 350 gear. It gets amazing mileage when I'm nice to it.
I've never built a small block per-se but always heard they favored a dual pattern cam. I'm not going wild with this build, it's just to replace the engine in my rpu, it's getting a little tired, not much oil pressure anymore. I pulled the 80,000 engine from a 63 Fairlane that had been sitting in a field for 15 years so it's done me well, I've rodded the beans out of it for 4 years now. I have a 64 260 to rebuild in my spare time.
The car only weighs 1900#, has a T5 and 350 gear. It gets amazing mileage when I'm nice to it.
Someone said you get 10.5 to 1 compression with 289HP heads on a 260. This seems strange, as both 289HP and plan 289 heads are 54.5 cc's. 260 heads are also 54.5 cc's. 221 heads are 45 cc's. So compression differences are done with the pistons, recessed, flat top or domed. The very earliest 289 heads may have been 45 cc's also, deep dish pistons would be needed.
The early 289 blocks were also 5 bolt bell housings, just like a 260, so maybe a 5 bolt 289 block is your answer.
If you use the GT40p heads, don't forget that the spark plugs are relocated and usually hit the header tubes, although your straight out tubes may clear. Either you will need to machine the heads for screw-in studs and adjustable rockers or spend hours figuring the exact pushrod length to run the OEM setup.
The early 289 blocks were also 5 bolt bell housings, just like a 260, so maybe a 5 bolt 289 block is your answer.
If you use the GT40p heads, don't forget that the spark plugs are relocated and usually hit the header tubes, although your straight out tubes may clear. Either you will need to machine the heads for screw-in studs and adjustable rockers or spend hours figuring the exact pushrod length to run the OEM setup.
willowbilly3
Well-known member
I got the book "How to Rebuild Your Small-Block Ford and absorbed most of that info but they didn't really touch on the 260 much and made no mention of the GT40-P.
When I was looking for a core to rebuild, I would have taken a 5 bolt 289 but a few wild goose chases and the 260 I bought is all that cropped up.
When I was looking for a core to rebuild, I would have taken a 5 bolt 289 but a few wild goose chases and the 260 I bought is all that cropped up.
willowbilly3
Well-known member
Ahh..thanks. I would probably have to find new header flanges and reweld my pipes.
JeffB2
Well-known member
You can use the oval header gaskets and get a seal but it won't seal the other way around.
