I don't have any personal experience with them but all of my research on them says that they are totally useless and a waste of money.
I'm with John on that, they are a waste of time and money. As for the main girdle.............John is correct again. When we had the 408 being refreshened, my machinist (Bob Gromm) showed me an interesting fact............he torqued the mains down to spec, then measured the inside bore (which had been line honed) and without the girdle they were right at the correct clearance, then he took the mains apart and added the girdle(both times with ARP main studs) and the mains were out of spec by .0005 to .001.............and he did this a number of times and each time the out-of-round fell within the same numbers. What this tells me is that it is close to impossible to pull the main girdle down and still have the main bearings/clearance be where it should be. Although it was $400 for the machine work, I added the three center 4 bolt mains to the early 351w block...................and I would never use a girdle again...........................IMHO
not totally useless. Just like the girdles.. they also help hold parts together after things go south with the block. I look at some of these new fangled parts like this. If they really were as good as the advertising would have you believe?.. then Dart, Brodix and World wouldn't be selling nearly as many blocks for hot street cars as they do these days. Not to mention that all the magazines would be using them on almost every buildup they do.
Now, rocker girdles do work, and quite well..................the only bottom end girdle that I thought was worth anything was one I designed for my 315hp Flathead V8 (with 141 Weiand blower).................but it tied into the pan rail and bolted to the center main bearing.........Flathead V8's only have 3 main bearings and a 75lb crank...............a lot of weight swing on three main bearings at 5200rpm.
I had to modify a pan to fit.............the hardest part was trying to make sure the pan rails were straight enough to make a good seal. I'll try and find a picture of the motor with the mod'd pan, unfortunately I sold the car just before I bought the Maverick and it's now in Finland.
when you use a main stud girdle, you line hone it with the girdle, like honing the block with the torque plate, a main girdle will keep the caps from walking, Ive never used a lifter valley girdle, but if you keep the engine on this side of 500hp, you wont need it. if you can make 480 hp, amd keep the car around 3000lbs with you in it, you can be in the tens, that's with the right converter, the right rear gear, and a set of tires that will 60fts in the 1.50s without spinning. keep the rpm around 8000, and you will be fine with a 2 bolt block. I ran one for years, and have seen a ton of 5.0 guys run in the 10s with them. duane
Thanks Duane, That's right where I should be when all is said and done. Line honing with the girdle torqued is definitely the way to do it.
My good friend Eric is machining everything. He manages a shop in the SeaTac area and has been machining since the early eighties.
I've always run a girdle, helps with cap walk and as others have said keeps your junk in one place after it blows. Less pieces to pick up.
Have a set of Scat I beams with the cap screw bolts on the way. Thanks again everyone for your opinions!