351w Swap

[sporkpork2006]

Hi I'm brand new to classicbroncos and would like to get yall's advice. I've been working on my fathers 1974 bronco and almost got it street ready. The 302 motor that's in it got blown by the mechanic and I want to switch it with a 351 Windsor. I already have one that just needs to be taken to a shop and machined but I don't know how much that's going to cost. I'd rather go with the most cost effective option and wanted to get an average price on how much it would be to take the 351 I have and get it rebuilt versus buying a crate engine. I've also been thinking about just buying a remanufactured 351 but I want to know what all I may be able to swap from the old 302 to the remanufactured 351 to save money and possibly labor. I'd love to hear your feedback.

 

[1969]

What’s your goal with the bronco?

 

[Broncobowsher]

I know this has been covered many times, but it has been a while.
The list of what is different is probably more important. Stuff that you can't use (or would take changes) off the 302 and use on the 351W

Intake manifold, it's wider
Distributor, the bore is slightly different and the oil pump shaft is different
Oil pan, the back of the pan at the rear main is different due tot he larger main bearings (the front isn't an issue)
Exhaust is a maybe. The heads being further up and out moves the exhaust ports up and out. Depending on how the exhaust is people had had true duals that just bolted up perfect, Y-pipes that needed some modifications, all the way to none of the old would work at all. Too many variables.
Accessory drives, head mounting points are relocated due to the heads further up on the taller block. Stock accessory drive, they make adaptor brackets for that. Cheap and easy, even keep stock belts.

Stuff that stays the same...
Timing cover forward. Same damper, same water pump, same alignment, same pulleys (You can get into issues trying to mix 351W later model damper, pulleys, etc, with early Bronco stuff)
The clutch, bellhouseing, trans, etc are all the same. The back of both blocks are exactly the same. There may be the clutch pivot bolt hole issue, but the Bronco venders all have a kit for that.
Motor mounts are the same.

In general the 351W is a 302 except the taller bock moves the heads up over an inch, and having to work around that. They also beefed up the main bearings, that makes for the oil pan issue. And the beefed oil pump drive that makes for the distrubutor issue. There is a lot of other beefing inside the engine

 

[73azbronco]

you need to search this forum, hundreds of topics on the subject

 

[sporkpork2006]

I know this has been covered many times, but it has been a while.
The list of what is different is probably more important. Stuff that you can't use (or would take changes) off the 302 and use on the 351W

Intake manifold, it's wider
Distributor, the bore is slightly different and the oil pump shaft is different
Oil pan, the back of the pan at the rear main is different due tot he larger main bearings (the front isn't an issue)
Exhaust is a maybe. The heads being further up and out moves the exhaust ports up and out. Depending on how the exhaust is people had had true duals that just bolted up perfect, Y-pipes that needed some modifications, all the way to none of the old would work at all. Too many variables.
Accessory drives, head mounting points are relocated due to the heads further up on the taller block. Stock accessory drive, they make adaptor brackets for that. Cheap and easy, even keep stock belts.

Stuff that stays the same...
Timing cover forward. Same damper, same water pump, same alignment, same pulleys (You can get into issues trying to mix 351W later model damper, pulleys, etc, with early Bronco stuff)
The clutch, bellhouseing, trans, etc are all the same. The back of both blocks are exactly the same. There may be the clutch pivot bolt hole issue, but the Bronco venders all have a kit for that.
Motor mounts are the same.

In general the 351W is a 302 except the taller bock moves the heads up over an inch, and having to work around that. They also beefed up the main bearings, that makes for the oil pan issue. And the beefed oil pump drive that makes for the distrubutor issue. There is a lot of other beefing inside the engine

This is perfect. Thank you

 

[walker_creek]

I think it helps to have a body lift for a Windsor too since the engine is taller.

 

[sporkpork2006]

I think it helps to have a body lift for a Windsor too since the engine is taller.

Yes I'm going to do a 2 inch body lift because it won't fit without

 

[sporkpork2006]

What’s your goal with the bronco?

To drive it around

 

[Broncobowsher]

you need to search this forum, hundreds of topics on the subject

Yes, but I don't recall one recently. Still things have not changed.

 

[tasker]

I will tell you one thing.....nobody has ever said " glad I took the 351 out and used a 302"

 

[sporkpork2006]

I forgot to ask but do you possibly think the clutch and bellhousing could be damaged because I'm pretty positive the timing chain cover is broken. So the mechanic left it in four low and test drove it and the engine blew. I got pissed and just got it towed home and just got the money to finally work on it. I'm worried about the transfer case and transmission being bad also because of how it went but I have a extra transfer case already. I just wanted to know that if the timing cover is broken, do y'all think that the waterpump, bellhousing, and clutch could also be damaged from the engine blowing.

 

[1969]

To drive it around

Oh

 

[Timmy390]

I forgot to ask but do you possibly think the clutch and bellhousing could be damaged because I'm pretty positive the timing chain cover is broken. So the mechanic left it in four low and test drove it and the engine blew. I got pissed and just got it towed home and just got the money to finally work on it. I'm worried about the transfer case and transmission being bad also because of how it went but I have a extra transfer case already. I just wanted to know that if the timing cover is broken, do y'all think that the waterpump, bellhousing, and clutch could also be damaged from the engine blowing.

I'm not sure someone who did as you say would rate the title of "mechanic". I would be calling him "the defendant".

To your question, with any high speed unexpected separation of rotating parts, you will only know what damage has been done once you get things disassembled.

Tim

 

[SteveL]

Yes I'm going to do a 2 inch body lift because it won't fit without

With the right intake and air cleaner a 351w can fit under a stock hood without a body lift.

 

[Broncobowsher]

I forgot to ask but do you possibly think the clutch and bellhousing could be damaged because I'm pretty positive the timing chain cover is broken. So the mechanic left it in four low and test drove it and the engine blew. I got pissed and just got it towed home and just got the money to finally work on it. I'm worried about the transfer case and transmission being bad also because of how it went but I have a extra transfer case already. I just wanted to know that if the timing cover is broken, do y'all think that the waterpump, bellhousing, and clutch could also be damaged from the engine blowing.

Can't tell until the parts are looked at. It sounds like the timing chain let loose and that took out the timing cover. With that in mind, it probably didn't hurt the clutch. But other damage may be present, wear, etc.

 

[Jfryjfry]

I have a 351w and can say having a body lift is really nice.

I used regular 302 headers but had to cut and weld the flanges at an angle and then adapt the exhaust to mate.

My wife decided she wanted an automatic so if you haven’t already bought the extended/adjustable clutch rod, I have a nearly brand new one along with some other stuff you might be interested in.

Message me here or email me at my username at yahoo

 

[Madgyver]

Build it yourself will be cheaper than a crate motor.
Machining costs can get up there so shop around.
Make it an educational task. It's cheaper than a tech school tuition.

 

[bulletpruf]

I forgot to ask but do you possibly think the clutch and bellhousing could be damaged because I'm pretty positive the timing chain cover is broken. So the mechanic left it in four low and test drove it and the engine blew. I got pissed and just got it towed home and just got the money to finally work on it. I'm worried about the transfer case and transmission being bad also because of how it went but I have a extra transfer case already. I just wanted to know that if the timing cover is broken, do y'all think that the waterpump, bellhousing, and clutch could also be damaged from the engine blowing.

The timing chain cover being broken wouldn't have anything to do with the clutch and bellhousing.

Test driving it in 4 low isn't terribly smart, but that wouldn't cause the engine to blow. Yes, you'll end up with higher rpm to move at a decent rate of speed, but you'd have to be a real idiot to run a 1974 302 up to 6k rpm or whatever it took to blow it.

I suspect your trans, bellhousing, water pump, and transfer case are fine, but you'll want to inspect everything closely.

Where are you located? Probably have a member nearby who can offer some input and advice in person.

 

[bulletpruf]

Hi I'm brand new to classicbroncos and would like to get yall's advice. I've been working on my fathers 1974 bronco and almost got it street ready. The 302 motor that's in it got blown by the mechanic and I want to switch it with a 351 Windsor. I already have one that just needs to be taken to a shop and machined but I don't know how much that's going to cost. I'd rather go with the most cost effective option and wanted to get an average price on how much it would be to take the 351 I have and get it rebuilt versus buying a crate engine. I've also been thinking about just buying a remanufactured 351 but I want to know what all I may be able to swap from the old 302 to the remanufactured 351 to save money and possibly labor. I'd love to hear your feedback.

The most cost effective and painless option is to find a running vintage 302 and drop that in as-is. You might get lucky and find someone selling one that you can see running before it's pulled so you know it's not smoking, has good oil pressure, etc. It might even make sense to buy a rusty 1970's F100 for $1500 just so you can yank the good 302 and scrap or part out the rest.

From there, the next most cost effective option is to find a good 302 core and rebuild it yourself. Depending on how badly your engine was "blown" you may still be able to use the oil pan, cylinder heads, etc.

And from there, next up would be a budget rebuild at your local machine shop, but be prepared for an extensive list of machine work that they recommend. $50 here, and $150 there and it will add up. If you don't know what you're doing, you could end up spending nearly as much at your local machine shop as you would spend on a brand new crate engine.

You could also find a later model fuel injected roller cammed 302 that would drop in as well and is less likely to need a rebuild, but then you have to deal with the issues associated with the later model engine. Lots of thread on that. These engines make real good power in stock form, and if you're just going to "drive it around" that will be all the power you need.

The 351 adds complexity because of the size, as already mentioned. If it's a late model 351, you also have the issues that you'd have with a late model 302, as noted above.

The best option, but one of the most expensive ones, would be a Blueprint engines 302 based crate engine. Lots of info on their website, but they have an excellent reputation and their engines are all dyno tested before leaving.

 

[pcf_mark]

I always go with the biggest engine I can afford so if you have a choice between building a 302 and 351 the 351 wins every time.

Not that I am questioning your experience but what make a motor "blown up"? Does it have compression and oil pressure? Is something physically broken like from an accident? This group could probably help getting an engine fixed running quicker and cheaper than a rebuild. If the timing chain cover is broke that is pretty wierd and may indicate cam bolts came loose but that seems pretty far fetched usually the fuel pump cam come off first then it stops running. Throw us some pics maybe we can help. More than one blown up engine has run again for many years with some attention.