Hello, my first post here. Starting on my 446 build. Wondering at what horsepower, rpm level big blocks need a main girdle? Im expecting 650 horse at the crank. Thanks!

No girdle here stock 400 block 12.1.1 comp. solid roller yada yada...........

Welcome to the board, there is a lot of controversary about main girdle use on Mopar BB Wedge motors do to the perceptions and myths spread by the manufactuers, vendors and some users on here I've seen at least three or maybe one or two more RB and 383 B motors crack the main webbing between the bottom of the cylinder walls into the main webbing, a girdle can't and will not fix that I made a race gas stock 440 block 526 C.I.stroker motor using ductile iron main caps that made 845 HP on a DTS engine dyno in Klamath Falls OR at 4300 Ft altitude in the spring several years back. I used that motor as a dyno mule and sold it to a freind and customer who has not raced that motor yet due to going trough some rough family probelms and then changing living up here to moving to Lake Havasu and that new track not opening yet down there My message is don't waste your time and money on a girdle, put it towards a lot better race block with 4 bolt main caps already cast and machined into it On your deal I would buy and have either Ductile iron or aluminum main caps and ARP main studs installed and align hone for your block I do that on all the stock Mopar BB wedge blocks I build now, I do try to build 400 blocks instead of the 440 blocks now though for anything at or above the pwoer level your shooting for All the stock 400 block main webs are a lot thicker than any of the production 413, 426 W or 440 blocks where Good luck on your build

Hmmm interesting. Well, the 650 horse is a rough guess because I'm going to use the new trick flow 240 head for the big blocks, and a 615/621 lift, 260/264 @.050 duration solid flat tappet from Hughes, at either 10.51 or 11-1 compression. I was reading a forum the other day on here and they had a 470 stroker with the same heads, not sure on cam, but 10.5-1 on pump gas and it made 675 horse @ 6,100 rpm. Im most likely going to use a factory forged crank unless a cast crank will hold up. Id like a forged one though.

Can`t speak for a girdle but will say I`ve been runnin the same 413 forged crank for 15 years and looked good on last two freshen ups and I assume I make that much w/my 470. Sounds like a nice combo and welcome aboard.............

The most basic upgrade is main studs and caps. I run Program steel caps at around 550 HP.

Current thinking, I believe, is aluminum caps are even better than steel as they absorb some of the shock load.

The old "rule of thumb" is 600 HP for long term durability. Plenty of engines exceed that... and some that do break. There are lots of other variables. B vs RB, individual blocks, piston weight and especially detonation. Personally, I'd feel OK with the main studs and aluminum caps at 650 HP as long as it is not a continuous running endurance type engine. Also use extra care on the tune... not too much timing and not lean.

550-600 is right around where you want to start considering a girdle. there are a lot of guys who run them very successfully and there are the naysayers who say you don't need one.

think of them as insurance. if you needed one and don't have one your outta luck. but if you didn't need one and you used what are you out?

yes we sell girdles. we have a lot of very happy users with our girdle kits. yes the first basic upgrade would be a set of aluminum main caps and some arp studs. after that a girdle.

check them out at bcrproducts.com then make your decision.

Well, for my goal, i found a calculator as a rough guess and it said i need 605 horse engine to get it down to where i need to be. Its going to get main studs and all that good stuff. Just need to know if its worth spending an extra 300+ on a main girdle setup. Going to use 440 source rods and pistons. It'll be in a 4,000 pound shortbed truck that'll see the strip quite often.

Girdles for Big Blocks in my opinion are just Band-aids. The things that have helped me are Aluminum main caps and ARP studs everywhere. I have had great luck with BCR caps, I know they sell a girdle as well that ties it all together but I have no experience with them.

I don't know that that combo will make 650HP but it should make good power.

Be careful if you start getting close to 700Hp this is what will happen:

#2

The short/stock stroke will help keep it alive longer, but at 600-650 hp I don't think you are in a dangerous place. I believe in aluminum caps and ARP studs, myself. Stock steel crank should give you decent life for a while. Find someone who can do a decent balance job. Don't skimp on the oiling system.
Welcome to Moparts.

It can't hurt.

Basically if you need more than studs and aluminum caps...you probably need an aftermarket block.

I am one of those in the "girdle doesn't help anything" camp. From an engineering point of view, it does nothing, because it doesn't address the problem. To me, it's a "what if" and "might help" type deal. Others see it different and that's fine. Like some others say, if the studs and alum main caps are not good enough for the power level, get a better block

I've seen major cap walk on stock stroke 440's in that power range WITH aluminum rods. It did get spun to 7800 a few times.

We ran them back when we ran stock blocks. Not sure if it really helped or not.

The caps still walked around, but we never broke a block. We were making 750-850 HP at the crank with 2 different motors. Made 100's of passes and they were still holding strong.

A stock block will be fine at 650HP with no girdle in my opinion.

We are making right around 700hp at 512 cubes with ours and we see slight cap walk....We run a girdle, and would highly recommend it at +600hp....We limit rpm and keep a close eye on everything.

We have 335 passes on our combo, and the light cap walk has shown no change from any of the freshen ups. Its been very light, and the rotating assembly still looks like new.

In my mind, rpm is the big killer..so we keep it down at 6400rpm...Granted one day it will let go, but its our race engine and if you race, its just a matter of time until something lets go..

Do you use stock caps with ARP studs?

If you have 300 or more bucks extra to spend on your build and are using a block that may be older then you,I really don't see the downside of installing a girdle. Even if the the added durability is minimal, the extra support could be the difference between BOOM or no boom.

I agree ^^ . At 650 hp with standard stroke it will be fine, buy some BCR ali cap and some ARP studs.

I have a 446 LY rod, cast crank engine with stock caps(my first race motor) that has a lot of runs on it and over 150 nitrous passes, best pass 9.69, it has a sleeve due to a pin walking out and wearing through the bore and in that pot is a manley piston that I shaped myself with a grinder to look like the 7 other TRW's That engine is now semi retired running NA 11.00's in my sons Aussie A body .