Well lessee... All the 5L guys run alloy heads. I guess there must be factory alloy heads since crate engines are popular, I also expect the flow on those is a good bit better than the baseline heads. Or the builder could buy a shortblock since aftermarket heads are dirt cheap. Good as an LS? I dunno, maybe. I suspect they are really close and would have to see flowbench results. Dan Jones should be asked to weigh in on this one. So that supposed advantage pretty much goes away. It's still just a glorified air pump, optimized for a specific RPM range. Both have roller cams, etc. Is that all you got? Nobody enjoys making custom headers. That's the end of the LS vs 5L Ford argument right there. If you have them made you must be made of money. So then why are you messing with MGBs in the first place? 5L headers are right there on the shelf in at least 2 styles. But apparently the Buick engines are just all wrong. Bad bore size, bad stroke length, bad valve sizes, shrouding problems, no room for roller cams, bad exhaust ports, bad intake, alloy heads too expensive and not as good as LS, no efi, no computer engine control and on and on and on. You guys have made a pretty good case. JB
Even the best ported aftermarket small block Ford heads do not come close to an off the shelf CNC ported LS3/l92 production LS head. Off the shelf CNC ported LS3/L92 heads flow 350 cfm at 28" on the intake. Stock LS3/L92 production LS heads flow 300 CFM! So, even if you could come up with a small block Ford head that flowed 350 cfm, you would have to wind it til' the moon to get it to run. Honestly, I don't know why it matters. I would work backwards from a specific performance goal, then pick a motor based on that. Exactly how fast do these conversions need to be? Here are some Small Block Ford Trick Twisted Wedge CNC Ported head Flow numbers: Airflow Data: CNC-Ported TFS TW Lift Intake/Exhaust 0.100 70/56 0.200 146/112 0.300 216/150 0.400 258/192 0.500 287/220 0.600 301/231 Read more: http://www.hotrod.com/techarticles/...l_block_ford_heads/viewall.html#ixzz1VIzEtRZ0 Here are some production casting L92/LS3 heads CNC Ported by PRC: Lift Intake Flow/Exhaust Flow .200" 154/115 .300" 223/170 .400" 282/198 .500" 324/211 .600" 351/228 Read more:http://www.texas-speed.com/p-1179-prc-ls3-and-l92-cnc-ported-heads.aspx We will not even mention the aftermarket L92/LS3 style head that eclipse 400 CFM. Even with saying all of this, it still might be far more practical to use the Ford small block because of the width of the motor.
Jim, my point was that the SBB was a better choice IMHO than the SBF for your application. If the Ford is easier to install in an MG it may be a better choice than an LS, FOR THAT APPLICATION, but it is NOT a better engine. If it was, Ford would still be using it instead of retiring it years ago. As far as torque goes I'm sure that a 340 or 350 SBB would have more and lower down than either the Ford or LS. The SBF were definately not torquey. The LS while it has a fairly flat torque curve does not make it's peak torque until 4000 rpm and that is quite noticable when pulling a heavy tailer, thank god for the 6 speed tranny.
So what is the relationship between CFM and horsepower? If 300 CFM puts you over 600 hp then the heads are not a limitation at all. And if that's the case then for the money and the ease of installation the 5L Ford beats the crap out of the LS. Once you reach the limit of what the block can take that extra 50 CFM buys you nothing. And let's face it, a MGB that'll run with a thousand horse GS has plenty of power. For any street driven car, more than that is way way beyond even the most extreme overkill. Plus, on the exhaust side the 5L heads flow BETTER. Face the facts. You can't build a LS based car that is comparable to a 5L Ford based car. To start with it'll cost way more money and since money is at the heart of the matter it just can't be done. And it can't be done any cheaper because it's all custom work and custom work is expensive. This is a swap that should only be considered by the most extreme sort of custom car builder as a long term project, because I can guarantee you it won't be done fast. For that you need a buyer with real deep pockets and enough patience to wait years, not months for the job to be finished. And those buyers are as scarce as hen's teeth. So the only way one of these cars does get built is by a master builder who for some god forsaken reason gets a wild hair up his arse and decides that for some reason known only to him, he's just got to have it at any cost. And that's just as scarce as your proverbial buyer. Rumors have it that one or two might have been built, but I'm well connected in the community and I've not seen one, or know anyone who has. Meanwhile there are literally dozens of Ford powered cars, and more being built all the time. That right there should tell you something. JB
I have a friend putting a 6.0 LS in his fox body mustang in place of the 5.0. The LS is lighter, stronger and faster out of the box. It is the pinnacle of pushrod performance and if I was going for a reliable, powerful cost effective build that would be my choice to recommend to others. For me personally its the SBB. If I am building a car I am building it for me and I feel that if there aren't guys willing to give the SBB a chance it will never be recognized as a viable contender to power older vehicles or heck maybe even newer ones (I love the idea of a fuel injected twin turbo Buick 350 in a turbo regal:grin But I emphasize the first line of the previous paragraph and that is "me personally". You should do what you want, what engine you like the best for whatever reason and say to heck with what others think (no offense intended). You have more than enough info in this thread to decide, I say build what you want and be sure to post a thread with pictures when you head that direction:beer
Bob - In a small car like the MGB, I would think in the interest of better handling, one might not want the weight penalty. (I realize we're not talking a HUGE weight difference). Plus, if you can up the bore & stroke of the 4.6 and get into the 300-320" range, you're not giving up a ton in cubes. Not to mention the extra strength of the cross bolted mains of the 4L and 4.6L blocks. Or, the factory EFI system.
That's a pretty broad statement. Narrow down the power level for comparison. Carb or factory efi? Which tranny? Factory heads or aftermarket? The only factory alum. ford 5L heads I'm aware of are the Cobra GT40X heads. Frankly, they're nothing to brag about. If you're talking AFR or Twisted Wedge, those are quality heads....but not very cheap. At what power level do you have to upgrade that fragile T5 to a rather expensive Tremec aftermarket piece?
Why not just put in a 3.8 Turbo V6 Buick motor. I have been to the track and seen these things operate. Smooth idle runs 10s in the quarter. We are now arguing about Ford against Chevy on a Buick site? Get a life people.
And that's really the point isn't it. Sure, a 6L LS is going to beat a 5L SBF in a Fox bodied Stang. That would surprise nobody. Plus it'll be an easy swap. Plenty of room and the Camaro headers will probably work. No new news here. And I think we've established at this point that a 5L SBF is a better choice for the MGB than an LS for a number of reasons but mainly for simplicity and cost of the swap. NOW we come to the heart of the matter. Is the 5L SBF a better choice than the SBB? If the earlier comments are anything that can be relied on then the answer would have to be yes. But honestly, I can't wait to see where this is going to go. JB
"Face the facts. You can't build a LS based car that is comparable to a 5L Ford based car" I'm pretty sure Jim was refering to building an MGB not any car. "NOW we come to the heart of the matter. Is the 5L SBF a better choice than the SBB? If the earlier comments are anything that can be relied on then the answer would have to be yes. But honestly, I can't wait to see where this is going to go." I think that all comes down to the level and type of performance you want. Do you want low rpm torque (SBB) vs hi rpm HP (Ford) per $$$ spent. If you are looking for something in the 350 HP range I'd go Buick, 450 HP range NA the Ford would be the cheaper, easier build. If you want to add turbos or a SC, the Buick would be better as it has a much stronger block. Also personal preforance comes into play; I would use the SBB just because I am a GM/Buick guy and not a Ford guy. If you wanted a basically stock engine with fuel injection, pick a 5L, if you want a carb then either would work. So there is no correct answer to this question, too many variables.
Bob - In a small car like the MGB, I would think in the interest of better handling, one might not want the weight penalty. (I realize we're not talking a HUGE weight difference). Jim has already asserted that the ~60 lbs weight difference isn't readily observable. as he's the experienced one in this arena, i'll defer to him. Plus, if you can up the bore & stroke of the 4.6 and get into the 300-320" range Buick 300 crank swaps have been all the rage for the Rover guys since, like, forever. that swap alone would take the 4.6L to just under 293ci.
I can tell you this on a comparison between a Buick and a Ford. I raced one of the next generation Fords (after 5.0) that had a supercharger on it when I had my nitrous running and on the highway out of second gear at about 40 mph we were door to door till I ran out of motor at 6 grand. Then we went around and came back down the highway and raced again but this time I got him slow enough so I could get into first gear and when we tromped on it I took him by a car length right off the bat and stayed there to 6 grand. I weigh 400 more lbs than the Ford Mustang. I am at 3800 lbs with me in it. So my conclusion is put the Buick motor in it get those good Hersch rods that are out there and put a supercharger or a turbo on it and you will beat just about anything out there. Plus still look nostalgic. The Buick 350 block is a M1 Tank. Can't say that about a 5.0 Ford. Ask my brother, he had to use a 347 block. I have been beating on my 350 for over 15 years on the same build and have gone well over 500 runs down the 1/4 mile. Ran nitrous for 4 years and my leakdown test was still over 90%. Buick wins. I have been beating on the same block since 1977. Put one of TA's rollercams in and I think you can easily get up to 500 horse with the 350 Buick, Use a solid lifter one. Build your own single plane and it will do it. With TA's new aluminum heads for the 350 the deal would be over for comparing anything. If the Buick guys that had a turbo or a procharger on it would get to the track and get some results then we would know what kind of power the 350 Buick really has. The whole summer has gone by and no one has posted anything. That is why you can't get any real comparisons. This is one crazy thread...
Not quite, but I can appreciate his comments. Still, if the SBF beats out the LS and the Buick is as good as the SBF, doesn't that mean the Buick beats out the LS? I mean, that was the original question. The way it stacks up is this. The LS may have the greatest power potential, fuel economy, and driveability, but it lacks bottom end torque and is outrageously difficult and expensive to install, so that swap is way out there. After all, just because you can put an Allison or Merlin in your '56 Chevy is no reason to do it. (and that swap has been done) Moving down the spectrum we'd come to the Buicks with power adders. Easy swap and the best bottom end torque but beyond the reach of most owners. Plus way way beyond anything that has ever been done so far, at a power to weight ratio approaching 2. Then the SBF, more costly and difficult because of interference with the frame and crossmember, less bottom end torque but good horsepower up to 600. Very likely the N/A Buick can be right there with it at about the same cost once the TA heads are available here. (cost of heads offset by cost of frame mods) But the SBB can be done for significantly less than the SBF if horsepower goals are more reasonable. Now we are entering the realm where most swaps live. Under 300 hp is the top of the bell curve, and that means the Buick 300, mild 302's, BOPR, and GM V6. Then dropping off the bottom of the curve are the blower installations for the stock 4 banger and high winding 4 cylinder builds. The Buick V6 would currently be here too, just because very few have been done and those that have were low powered N/A builds. Very good torque though. In reality, the SBF only inhabits a very specific part of the spectrum. It is not competitive below 300hp because of cost. It is not competitive above 600hp because of block strength. A 300hp range seems like a lot but again the bell curve comes into play and is centered pretty closely around the 375hp factory crate engine, so the practical range is a lot closer to 325-400hp. So there you have the basic distribution. The real sleeper in this whole mess is the 300 Buick. Competitive with the 302, it is very likely the cheapest swap that can be done, with the most bang for the buck. It's cheaper because a late model car has only one issue with it and that is hood clearance. It's cheaper because it uses a $25 bellhousing instead of a $200 one and a $30 flywheel instead of a $200 one. It's cheaper because the headers and motor mounts for this swap have been around longer than any others. It's cheaper because there are no new problems to be solved and a well trodden path to follow. Finally, and far from least, it has as much or more performance potential as any other reasonable candidate. It can be easily stroked to 350ci and this has been done and proven. The block is good to 1000hp with power adders. And as we speak TA is selling their first run of heads for it. Work with the 350 has shown that a roller cam can be made to fit it. Crank trigger ignitions are in use. Rover EFI can be used with a set of simple spacer plates, which are available. Roller rockers have long been available. Modern neoprene crank seals are commonplace. Engine management is a phone call away, in the flavor of your choice. What's left to turn this into a thoroughly modern engine? The proper selection of pistons, rings and rods? Not really a problem. Oh, and although the SBB community sort of looks down at the '64 alloy heads because they do not flow nearly as well as the later iron heads, they beat out anything and everything in the 215/Rover (BOPR) community short of aftermarket and those engines can easily top 250hp, so the alloy 300 heads are an excellent low cost light weight choice. Speaking of weight, the BOPR shaves approx. 30 lbs off the stock vehicle weight. The '64 300 adds back about 60 lbs. And an extra 30 on the front end of the car will not even be detectable. But the extra power and torque sure will be. JB
The 300 is cheap alright. I had a perfect running 300 with matching trans that I literally could not give away. That is as cheap as it gets.
Wish there was someone around here who couldn't give a 300 and matching transmission away! I would fill my garage with them for that price. Good little engine.
That is what I do, stockpile Buick 350s...:beers2: I pay very little for them, some are even free!:Brow:
I would love to see someone do a Buick 350 MGB swap. But I suspect the engine height might be a little bit of an issue. Plus headers. Plus probably engine mounts. And the steering might have to be changed some. Then there's the extra weight of the iron heads. But it'd be the only one of the Buick line, excluding earlier engines, that we haven't done and I think it'd make a pretty good swap once it was done. Pretty phenomenal performance potential too. JB
Wish I could find some cheap or even for free around here..... Been looking Hard with no LUCK............. As for comparison LS vs Buick. Thats like comparing apples to oranges. From What I can see this is a never ending debate depending on which side of the fence you are on......
