Splayed main caps on a 360?

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Cope

Cope

Fusing with fire
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What are your thoughts on adding the 4 bolt caps to my small block blower build?

7-10 pounds of boost, hopefully making right around 600 HP at the crank.

Some say it removes strength in an already weak area some say it helps.

I dont plan on turning much over 6,000 RPM.

thoughts?
 
Heres my rough build.

360 block bored 30 over.
408 forged crank and H beam rods.
Custom forged pistons.
8 to 1 compression.
Double key way.
Speed master heads.
ARP studs and bolts.
6-71 roots blower at 7 Lbs.

Billet 4 bolt main caps?
Girdle?

What am i missing or how would you build it?
 
I'm not convinced 4 bolt caps in a standard block are worth anything. The power level is fine for 2 bolt aftermarket caps. If it was me I'd use lighter rods, or aluminum unless you subscribe to the "timebomb" theories (I don't). Girdles are for old ladies. If you think you need a girdle, get a better block.
 
I say no as there is no need. I state this based on factual evidence. When was the last time you have seen or heard about someone spitting a crank out the bottom end? I go with about a 500 to 550 hp break over point as long as everything is sound to start with.
 
I mentioned 4 bolt mains to my engine builder (an old school hardcore ford guy) he got a really good laugh out of that...
he gave me a quizzical look as if there was something wrong with my brain and said "have you ever seen the size of a Mopar main Bolt?!"... He said highly unnecessary...
 
What you should do is contact FABO member Rocket and buy a compete set of ductile iron caps from him. He has them for an exellent price.
Use those and studs and that's about as good as you can do with a Pcar block.

There isn't nearly enough materiel in the Pcar block to warrant a bolt out there. Guys do it, but it's a bad idea. That I filled pan rail isn't very strong and putting a bolt hole there, and loading it, even with 45 pounds of torque is just asking for a fracture to occur. And it usually does.
 
Personally I would never add four bolt main caps to a 360 block. Then again if I ever found the need to upgrade my main caps they would be aluminum but I haven’t found that need yet. My opinion and 4 bits would probably be worth a cup of coffee. Goodluck
 
No need to add 4 bolt main caps only spinning 6K.
 
Ok so the 4 bolt caps are out.


ARP studs and line hone it is.

Even at low compression lets say i make 1Hp per cube, add 7PSI thats 408+204 that puts me right were i wanna be.

My engine builder should be able to make that happen easy i would think?
 
RustyRatRod said:
No need to add 4 bolt main caps only spinning 6K.
Click to expand...

RPM is just one of the things to look at. How about rotating weight of the stroker assemble verses weight of the stock rotating assemble? More compression equals more force. Then you have the lenght and weight of the fuel line and filter.
 
pittsburghracer said:
Or better yet put studs in it and see if it needs line bored. I’ve never had to do one yet and from what I hear that helps with timing chain issues.
Click to expand...

I have a set of Rockets 4 bolt caps that are going on a block that had the wrong caps. I am cutting the extra outer hole area off and align bored and then honed.
That is why I say stud and align bore.
The studs are 20 or 30 ft lb tighter than bolts so that helps with cap walk.
 
I figured the added weight and pistion speed should not be an issue as im running a roots blower so no need for high RPMs.

I think the stroker on 7 psi should be a street stomping machine and enough to get me down the track at a good clip.

My car is FULLY gutted, all aluminum interior, custom 9", spool, 35 spline chrome molly axles, 12 point cage, frame connectors 29x10.5 DOT drag radials and all the good stuff...
 
Jadaharabi said:
RPM is just one of the things to look at. How about rotating weight of the stroker assemble verses weight of the stock rotating assemble? More compression equals more force. Then you have the lenght and weight of the fuel line and filter.
Click to expand...

Then put the 4 bolt caps on it.
 
yellow rose said:
What you should do is contact FABO member Rocket and buy a compete set of ductile iron caps from him. He has them for an exellent price.
Use those and studs and that's about as good as you can do with a Pcar block.

There isn't nearly enough materiel in the Pcar block to warrant a bolt out there. Guys do it, but it's a bad idea. That I filled pan rail isn't very strong and putting a bolt hole there, and loading it, even with 45 pounds of torque is just asking for a fracture to occur. And it usually does.
Click to expand...
Cheeseburger...
 
Cope said:
Ha ha, do you jave the cheeseburger birds in Portland?

In tahoe they are everywhere!
Click to expand...
I've been trying to get yellow rose to show up somewhere anywhere obviously it's not going to be at the drag strip.. I keep telling him to buy me a cheeseburger or something just prove he's human...lol..
Still nothing...
Have you already got the Speedmaster heads?..
 
Officially he is a teenage girl with a stack of her father's hot rod magazines giving us information... Until proven different...
 
All i have is the blower, manifold, carbs and a spare 360 block.

But im getting to the point where i can start spending some money on the new engine build!

Its not gonna be a "skys the limit" build but im not gonna go cheep on it.

The heads dont even really concern me as its forced induction so i would slap my cast iron ones on bit i want the aluminum to remove some heat because the blower will be making my charge air hot!
 
Cope said:
All i have is the blower, manifold, carbs and a spare 360 block.

But im getting to the point where i can start spending some money on the new engine build!

Its not gonna be a "skys the limit" build but im not gonna go cheep on it.

The heads dont even really concern me as its forced induction so i would slap my cast iron ones on bit i want the aluminum to remove some heat because the blower will be making my charge air hot!
Click to expand...
Well Black Friday is just around the corner. I'm sure you can get cnc-ported ones for pretty cheap...
I'm sure you seen where I got my unported ones for 820 to the door...
 
Im gonna buy them unported. My builder is a wizard with the grinding burr.

I will post the numbers when i get to that point.

Where did you biy yours? Thats a good price!
 
Cope said:
Im gonna buy them unported. My builder is a wizard with the grinding burr.

I will post the numbers when i get to that point.

Where did you biy yours? Thats a good price!
Click to expand...
I bought mine direct from Speedmaster..
The website is speedmaster79... I got mine near the weekend of September 11th and they were having a 30% off sale... For unported with no valves or anyting they were $255 each... Free shipping over $100.. I would be surprised if they didn't have it on Black Friday but I watch it all the time or I have their app on my phone and take a peek each day to see if the sale is on again... I still need to get my head studs and they also sell the intake manifold gasket that matches the Fel-Pro 1213 for like twelve bucks instead of 26 or more...
 
Cope said:
Im gonna buy them unported. My builder is a wizard with the grinding burr.

I will post the numbers when i get to that point.

Where did you biy yours? Thats a good price!
Click to expand...
Also after I run mine for a year or two I like it champion have someone give them a professional port and valve job...
 
Please let me know if you see them at a good price.

I want bare, unported.


Here is the cheeseburger bird.
 
My guy is good. The bad news is he is super expensive. The only reason I can afford him is that when im not crazy busy i go nextdoor to his shop and do all the stuff he dont want to do for free. (Wiring, installation, plumbing, ect.)


Just got my new power probe 4 and ect 3000 a few days ago. Cant wait to use it. Got two wiring jobs coming up.
 
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