351 Windsor hp limit? head options?

1968-coupe · Oct 25, 2010

I found a great deal on a 351 windsor engine (disassembled, $100) Im mainly interested in the block, which had a piston crack so it will need to be bored (its factory bore now)

What is the HP limit that a factory 351 block can handle? Is it more than that of a stock 302? I may end up building this 351 block up if it can safely handle 500hp.

Also would I see more power with a good set of 351 Cleveland heads on it or are there 351W heads that will flow just as well?

2+2GT · Oct 25, 2010

Ford now sells a 427 c.i.d. version of the 351W, you could probably study that engine for ideas. And while it's possible to install 351C heads on a Windsor, it's an uneccesary PITA.

brianj5600 · Oct 25, 2010

A windsor block will take well over 500. I think 850 is more like it for a 351w if you don't rattle it.

1968-coupe · Oct 25, 2010

Im really wanting to come in around the 500 mark. I gave up on the 302 after being told that 450 is its limit for a stock block. Im REALLY into the Clevors, its different. Still new to me though. I wanted to build a cleveland but after stumbling on this I may go the Clevor route.

What do I do about headers for a 68 coupe running Cleveland heads? Will 1970 headers work?

65coupe408w · Oct 26, 2010

build a 408w stroker with 10.5:1 compression good set of heads and a custom grind cam and 500hp on pump gas will be pretty easy.

Wicked65 · Oct 26, 2010

Typically, if you dont rev over 6500ish, 600 at the crank is the "safe" limit. Plenty of people make more then that, so its not like it cant be done. But thats kinda my personal Limit on the subject. Note if you do a zero balance, lightweight internals, debur block....ect it might be able to take more.

rbohm · Oct 26, 2010

like the other said, as long as you keep the revs below 6500, the stock windsor block can handle well over 500hp, the upper limit being around 700hp or so.

as for heads, the cleveland heads can certainly be put on the 351w block, and they look cool imo, but there are plenty of better choices these days that are direct bolt ons without having to find clevor intakes, and do some machine work on the heads to make them work properly. for a 500hp motor, i would drop on a set of world products windsor sr heads, either cast iron(on a budget), or aluminum, or any of the other aftermarket heads with an intake runner of at least 200cc.

1968-coupe · Oct 27, 2010

I like the Clevor idea, I really wanted to build a Cheveland engine, but stumbling across this windsor got me thinking Clevor. As for the intake Edlebrock makes one, and there are a large vriety of Cleveland heads that will work great for the clevor. I have played around with 302s for a while now so im tired of that and looking for something different, like a cleveland.

What headers work in a 68?

brianj5600 · Oct 27, 2010

I have never heard of a windsor block cracking below 800hp. I also think that World Product sbf heads are probably some of the worst non Ford heads made. A clevor does have some cool factor, but they are not cheap or easy. Cleveland heads can make great power too, but the ports are big for what they flow. You could fool most people by putting Cleveland shaped valve covers on windsor heads. That would also get rid of the head ache of trying to get pistons and headers with out giving up performance. Headers might not be a problem since the C and W blocks have such similar deck heights, but when dealing with large primary tubes and shock towers there is very little room for error. I would not be surprised if a clever ended up costing $2000 more to build.

1968-coupe · Oct 27, 2010

I have never heard of a windsor block cracking below 800hp. I also think that World Product sbf heads are probably some of the worst non Ford heads made. A clevor does have some cool factor, but they are not cheap or easy. Cleveland heads can make great power too, but the ports are big for what they flow. You could fool most people by putting Cleveland shaped valve covers on windsor heads. That would also get rid of the head ache of trying to get pistons and headers with out giving up performance. Headers might not be a problem since the C and W blocks have such similar deck heights, but when dealing with large primary tubes and shock towers there is very little room for error. I would not be surprised if a clever ended up costing $2000 more to build.

$2,000? Seriously? I was expecting to spend $7-8,000 on just the engine.

brianj5600 · Oct 27, 2010

The cost of the windsor + $2000 = clevor cost.

1968-coupe · Oct 27, 2010

Im picking up a Windsor this weekend. As for the build im only using the block, olus:
SCAT rotating assembly = $2,000
Truckflow 190 Clevland heads = $2,000
plus everything else I will need, Cam, intake, and 750 Holley 4bbl will make that $5,000 plus everything else the engine requires. Total tag is between $7-8,000.

ForceFed70 · Oct 27, 2010

I'v always been told that 700HP is the safe limit for the 351W block. But many seem to have had luck running more than that.

ashford · Oct 27, 2010

ForceFed70 said:
I'v always been told that 700HP is the safe limit for the 351W block. But many seem to have had luck running more than that.

it depends on the years. 69-72 blocks have seen 1000hp on turbo low rpms,
73-83 are the weakest but still way better than 302.
83 ho to whenever they stoped are the next most desirable and the roller blocks are midgrade- there are alot of 700hp turbo roller blocks

1968-coupe · Oct 27, 2010

It may be next weekend before I can pick this one up. I will post the casting numbers. It came out of an early 80s F150 hotrod. mild cam, punched .030 over (it had a piston crack it will need to be bored again) Edlebrock intake, it had a Holley 750 on it. Not sure what head work was done. Im getting the entire dieassembled engine so if anyone is looking for parts i will be selling what I dont need. I will probably end up using just the block.

blown65 · Oct 28, 2010

brianj5600 said:
I have never heard of a windsor block cracking below 800hp. I also think that World Product sbf heads are probably some of the worst non Ford heads made. A clevor does have some cool factor, but they are not cheap or easy. Cleveland heads can make great power too, but the ports are big for what they flow. You could fool most people by putting Cleveland shaped valve covers on windsor heads. That would also get rid of the head ache of trying to get pistons and headers with out giving up performance. Headers might not be a problem since the C and W blocks have such similar deck heights, but when dealing with large primary tubes and shock towers there is very little room for error. I would not be surprised if a clever ended up costing $2000 more to build.

X2

I'd either go AFR 205's or some TFS HiPorts. Personally I'd do the hiports just because you can go much further down the road than with the afr's.

If your stuck on a clevor setup, I'd do some C3 heads and ditch the heavy ass cast iron deal.

68RCodeConv · Oct 28, 2010

500 hp out of 351 cubic inches is doable but I'm not sure how drivable it will be. You are talking about a pretty radical cam that probably won't make much vacuum and the idle quality won't be very good. Plus below 2500 it will not pull great.

In my 347 (worked Dart Pro 1 heads) I had a 240/249 duration at 050 cam with 108 LSA and .570 lift. 4 inches of vacuum, would not idle below 1100, did not smooth out until 2000 rpm. It did not make anywhere near 500 hp. It was an awful combo in urban driving.

1968-coupe · Oct 28, 2010

blown65 said:
X2

I'd either go AFR 205's or some TFS HiPorts. Personally I'd do the hiports just because you can go much further down the road than with the afr's.

If your stuck on a clevor setup, I'd do some C3 heads and ditch the heavy ass cast iron deal.

Im going with aluminum Trick flows most likely.

500 hp out of 351 cubic inches is doable but I'm not sure how drivable it will be. You are talking about a pretty radical cam that probably won't make much vacuum and the idle quality won't be very good. Plus below 2500 it will not pull great.

In my 347 (worked Dart Pro 1 heads) I had a 240/249 duration at 050 cam with 108 LSA and .570 lift. 4 inches of vacuum, would not idle below 1100, did not smooth out until 2000 rpm. It did not make anywhere near 500 hp. It was an awful combo in urban driving.

That had worried me, The thing abour the clevor is that its not making power below 1500 RPMs in even a mild build. I LOVE a lumpy idle, but I guess I will have to experiment and find a happy medium between performance and drivability. I can always shange the cams out and go milder.

BuckeyeDemon · Oct 28, 2010

i have TFS high ports in a 69 mustang with a 351W block.

fitting the headers was a major PITA. i relocated the clutch linkage, completely cut two primaries and rerouted by welding mandrel bends.

and i'm only using 1 3/4" long tubes.

if you decide to go with TFS then consider the TW's instead. Unless you don't mind some fab work.

blown65 · Oct 28, 2010

68RCodeConv said:
500 hp out of 351 cubic inches is doable but I'm not sure how drivable it will be. You are talking about a pretty radical cam that probably won't make much vacuum and the idle quality won't be very good. Plus below 2500 it will not pull great.

In my 347 (worked Dart Pro 1 heads) I had a 240/249 duration at 050 cam with 108 LSA and .570 lift. 4 inches of vacuum, would not idle below 1100, did not smooth out until 2000 rpm. It did not make anywhere near 500 hp. It was an awful combo in urban driving.

Sounds like you had a screwed up combo TBO. My cam is much bigger than that and I can even get mine to idle just fine at 1000. Of course its still pretty rough up around 2000. 270'sI/280'sE and 700+lift.

I would think someone doing a 351 from scratch would at least do a 408 stroker in it. With the inexpensive kits out there now at least.

You could do a very streetable build out of a 408 and make 550-600hp without hardly trying. Just takes some of the right parts and the right camshaft. I learned my mistakes by listening to people that knew nothing about performance Fords and started looking at what ppl were doing with them to make them go fast. Go check out some of the builds on hardcore50 dot com and you will get some ideas of what can be done. Quite a few very fast street cars with street friendly builds.

351 Windsor hp limit? head options?

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