Do I need Splayed Main Caps?
Thread Starter
Melting Slicks
Joined: Dec 2001
Posts: 2,025
Likes: 1
From: Billings MT
Do I need Splayed Main Caps?
I am building a 406, the specs and parts are as follows:
400 Block, 2 bolt Mains, ARP Main Studs, Deck Plugs
SCAT 9000 Series 400 Crank for 6.0" rods
SCAT H-Beam 6" Rods
SRP Forged Flat Tops
AFR 195cc Street Heads
Comp Cams Xtreme Roller 288 Hydraulic Roller Cam
236/242 @ .050 .520/.540 110LS 106ICL
Crane Hydralic Retrofit Lifters with Vertical Locking Bar
I would like to slightly over 500 hp/tq with this setup, and
it should make peak power at ~6000rpm, and probably won't
be spun higher than 6300.
Will I be ok with the studed 2 bolt main caps?
Or is it necessary to go with the splayed caps?
Thanks. :cheers:
400 Block, 2 bolt Mains, ARP Main Studs, Deck Plugs
SCAT 9000 Series 400 Crank for 6.0" rods
SCAT H-Beam 6" Rods
SRP Forged Flat Tops
AFR 195cc Street Heads
Comp Cams Xtreme Roller 288 Hydraulic Roller Cam
236/242 @ .050 .520/.540 110LS 106ICL
Crane Hydralic Retrofit Lifters with Vertical Locking Bar
I would like to slightly over 500 hp/tq with this setup, and
it should make peak power at ~6000rpm, and probably won't
be spun higher than 6300.
Will I be ok with the studed 2 bolt main caps?
Or is it necessary to go with the splayed caps?
Thanks. :cheers:
Race Director
Joined: Feb 1999
Posts: 12,772
Likes: 17
From: Indianapolis IN
Re: Do I need Splayed Main Caps? (VETDRMS)
Depends on the block, what casting number GM, 509, 511 etc?
I am building virtually an identical setup to yours except I'm using the AFR 210CC heads. My engine builder says not to splay my GM 400 that is a 509 casting number. He told that me that it actually makes the block weaker. :seeya
I am building virtually an identical setup to yours except I'm using the AFR 210CC heads. My engine builder says not to splay my GM 400 that is a 509 casting number. He told that me that it actually makes the block weaker. :seeya
Thread Starter
Melting Slicks
Joined: Dec 2001
Posts: 2,025
Likes: 1
From: Billings MT
Re: Do I need Splayed Main Caps? (ld85)
ld85 Thanks, I was looking at the 210's as well, but I think it would hurt my low end and responsiveness. I need to remind myself that this motor IS for the street, I want it snappy, and powerful. :cheers:
It is a 509 Block, picked it up for $100 from my machinist, already cleaned checked and ready to machine. :cheers:
Monty Thanks, I can apply the 300-400 dollars to something more useful then. Your car is looking great! I wish I was still going to school in Chicago, I'd love to see it. I'll be there this summer for a bit, maybe take a look? :) I went to IIT down on 31st and Michigan, well, actually off of State St.
It is a 509 Block, picked it up for $100 from my machinist, already cleaned checked and ready to machine. :cheers:
Monty Thanks, I can apply the 300-400 dollars to something more useful then. Your car is looking great! I wish I was still going to school in Chicago, I'd love to see it. I'll be there this summer for a bit, maybe take a look? :) I went to IIT down on 31st and Michigan, well, actually off of State St.
Le Mans Master
Joined: Mar 1999
Posts: 6,744
Likes: 1
From: delmont pa
Cruise-In I Veteran
Cruise-In II Veteran
Re: Do I need Splayed Main Caps? (VETDRMS)
i would be conserned about what material the caps are made from because the stock cast iron caps are only good for 400 HP and the nodular iron caps are good for 450 HP after that i would use steel caps with 2 bolt mains. the downward pressure on the caps pull them inward and then they move around because they no longer are a tight fit in the block. you could dowel pin the caps to the block and this will prevent the caps from pulling inward. i always did this on any 2 bolt engine not just chevys. :chevy
I am building a 406, the specs and parts are as follows:
400 Block, 2 bolt Mains, ARP Main Studs, Deck Plugs
SCAT 9000 Series 400 Crank for 6.0" rods
SCAT H-Beam 6" Rods
SRP Forged Flat Tops
AFR 195cc Street Heads
Comp Cams Xtreme Roller 288 Hydraulic Roller Cam
236/242 @ .050 .520/.540 110LS 106ICL
Crane Hydralic Retrofit Lifters with Vertical Locking Bar
I would like to slightly over 500 hp/tq with this setup, and
it should make peak power at ~6000rpm, and probably won't
be spun higher than 6300.
Will I be ok with the studed 2 bolt main caps?
Or is it necessary to go with the splayed caps?
Thanks. :cheers:
400 Block, 2 bolt Mains, ARP Main Studs, Deck Plugs
SCAT 9000 Series 400 Crank for 6.0" rods
SCAT H-Beam 6" Rods
SRP Forged Flat Tops
AFR 195cc Street Heads
Comp Cams Xtreme Roller 288 Hydraulic Roller Cam
236/242 @ .050 .520/.540 110LS 106ICL
Crane Hydralic Retrofit Lifters with Vertical Locking Bar
I would like to slightly over 500 hp/tq with this setup, and
it should make peak power at ~6000rpm, and probably won't
be spun higher than 6300.
Will I be ok with the studed 2 bolt main caps?
Or is it necessary to go with the splayed caps?
Thanks. :cheers:
Thread Starter
Melting Slicks
Joined: Dec 2001
Posts: 2,025
Likes: 1
From: Billings MT
Re: Do I need Splayed Main Caps? (clem zahrobsky)
Monty Wow, that would be awesome. :cheers: If i hit my 500 mark with this motor I think that experiance will cause me to go into a spending fest upon returning home! :lol: :lol: My better half will have my head for it! :lol:
Clem Zahrobsky Thank you, all good information. How much is it to have the mains dowled? Also, where could I get the steel caps?
Oh, one more thing. I am having a rather difficult time deciding on which head to use. I like the AFR's, but here some issues about quality quite often, and I can't get them without AFR's parts. :cuss I would like to get a pair of Dart Pro 1 200 or 215cc heads, and with some bowl work and light port work could i still get past the 500 mark???
Thanks!
[Modified by VETDRMS, 8:20 PM 2/28/2003]
Clem Zahrobsky Thank you, all good information. How much is it to have the mains dowled? Also, where could I get the steel caps?
Oh, one more thing. I am having a rather difficult time deciding on which head to use. I like the AFR's, but here some issues about quality quite often, and I can't get them without AFR's parts. :cuss I would like to get a pair of Dart Pro 1 200 or 215cc heads, and with some bowl work and light port work could i still get past the 500 mark???
Thanks!
[Modified by VETDRMS, 8:20 PM 2/28/2003]
Le Mans Master
Joined: Mar 1999
Posts: 6,744
Likes: 1
From: delmont pa
Cruise-In I Veteran
Cruise-In II Veteran
Re: Do I need Splayed Main Caps? (VETDRMS)
i did all my own doweling so i have no idea what a shop would charge. check you local speed machine shop for a price and how and where to get steel caps. i have been retired for 10 years so i am a little out of touch with suppliers these days. :chevy
Corvette Stories
The Best of Corvette for Corvette Enthusiasts
5 Best & 5 Worst Corvette Daily Drivers
Joe Kucinski
The Headlights of Every Corvette Generation Explained
Joe Kucinski
5 Best & 5 Most Overrated Corvette Track Packages of All Time!
Joe Kucinski
Every 2027 Corvette Engine Explained
Joe Kucinski
Designer Imagines A Corvette That Looks More Like a Corvette Than the Corvette
Verdad Gallardo
10 Ugly Corvettes That We Still Kinda Love
Joe Kucinski
Top 10 Most Expensive Corvettes Ever Sold on Bring A Trailer
Brett Foote
10 Things Every Corvette Owner Needs (2026 Edition)
Michael S. Palmer
8 Most "Only Corvette Owners Understand" Quirks and Problems
Pouria Savadkouei
Race Director
Joined: Dec 1999
Posts: 16,945
Likes: 9
Re: Do I need Splayed Main Caps? (clem zahrobsky)
I agree with the others that you don't need splayed mains but steel caps would be good insurance. You'll definately need studs.
Now if you're going with steel caps you'll have to have machinery done on them to get them inproperly, this is where the splayed caps start to become interesting again as for not much more $$$ you can have your block drilled and tapped for splayed mains.
Marck
[Modified by Twin_Turbo, 3:46 AM 3/1/2003]
Now if you're going with steel caps you'll have to have machinery done on them to get them inproperly, this is where the splayed caps start to become interesting again as for not much more $$$ you can have your block drilled and tapped for splayed mains.
Marck
[Modified by Twin_Turbo, 3:46 AM 3/1/2003]
Race Director
Joined: Feb 1999
Posts: 12,772
Likes: 17
From: Indianapolis IN
Re: Do I need Splayed Main Caps? (VETDRMS)
[QUOTE I am having a rather difficult time deciding on which head to use. I like the AFR's, but here some issues about quality quite often, and I can't get them without AFR's parts. :cuss I would like to get a pair of Dart Pro 1 200 or 215cc heads, and with some bowl work and light port work could i still get past the 500 mark???[/QUOTE]
I too have struggled with this. Spoke to a porting place yesterday and they said that AFR quality is poor, Canfield quality is poor, so you wonder what is a good head for reasonable money for a 406!? A 350 has more options I think! Let us know if you talk to a Dart person. I'm going to call a company that is local "Indy Heads" this weekend and talk to them.
I too have struggled with this. Spoke to a porting place yesterday and they said that AFR quality is poor, Canfield quality is poor, so you wonder what is a good head for reasonable money for a 406!? A 350 has more options I think! Let us know if you talk to a Dart person. I'm going to call a company that is local "Indy Heads" this weekend and talk to them.
Thread Starter
Melting Slicks
Joined: Dec 2001
Posts: 2,025
Likes: 1
From: Billings MT
Re: Do I need Splayed Main Caps? (clem zahrobsky)
Clem Zahrosbsky Ok, i'll talk to him monday, I haven't been able to find any 2 bolt steel caps for a 400. Do I need to replace just the center three? or the front and rear ones too? I know the rear one can be a little weak, but could I just enforcet that with a steel plate?
Twin_Turbo I have the ARP studs already, and am having trouble finding the steel caps. I was already going to have the mains align honed, so I don't count that as an additional cost. I will talk to my machinist monday and see what he says. Thanks :cheers:
ld85 The people I've found to like Dart are people who actually race, a lot. Also, "out of the box" the Dart's are spectacular, but they can get some pretty amazing numbers out of them with work. From what I hear on the darts is they have a better combustion chamber with less shrouding, and better port velocities. Its a hard call, every magazine LOVES the AFR's, the people who don't sell them, have either not seen them, or weren't impressed. Its a tough call, and very frustrating! :smash:
Twin_Turbo I have the ARP studs already, and am having trouble finding the steel caps. I was already going to have the mains align honed, so I don't count that as an additional cost. I will talk to my machinist monday and see what he says. Thanks :cheers:
ld85 The people I've found to like Dart are people who actually race, a lot. Also, "out of the box" the Dart's are spectacular, but they can get some pretty amazing numbers out of them with work. From what I hear on the darts is they have a better combustion chamber with less shrouding, and better port velocities. Its a hard call, every magazine LOVES the AFR's, the people who don't sell them, have either not seen them, or weren't impressed. Its a tough call, and very frustrating! :smash:
Le Mans Master
Joined: Mar 1999
Posts: 6,744
Likes: 1
From: delmont pa
Cruise-In I Veteran
Cruise-In II Veteran
Re: Do I need Splayed Main Caps? (VETDRMS)
years ago before aftermarket caps we would surface grind the bottom of the 4 front caps flat and the use a 7/8"X 7/8" square steel bar with longer studs under the caps to add strength. the front one may cause pan interferance so if you do not want to modify the pan do not use the steel bar on it. :chevy
Le Mans Master
Joined: Mar 1999
Posts: 6,744
Likes: 1
From: delmont pa
Cruise-In I Veteran
Cruise-In II Veteran
Re: Do I need Splayed Main Caps? (clem zahrobsky)
checking thru my files i found out that we also made a rear cap plate,but it was not flat. we ground the rear cap so the distance from the oil pump mounting surface to the place where the studs mated was a specific dimension and then made a steel cap with this step in it. this also lowered your oil pump but we were using deeper oil pans so this was not a problem. these were 400 blocks use for alky burning short track engines. :chevy
Thread Starter
Melting Slicks
Joined: Dec 2001
Posts: 2,025
Likes: 1
From: Billings MT
Re: Do I need Splayed Main Caps? (clem zahrobsky)
Clem Zahrobsky
Thanks, I was going to be using a 7qt pan with a baffle, tray and scraper, so if need be I can do soemthing different and modify the pan. I just don't want the bottom end of my motor coming apart!
That is the rear cap plate I was thinking about, I may just try to dig up a set of steel caps, or possibly just go splayed, just getting stretched thin, college, car, running my business, plus girlfriend makes things tough alll over :) hehehe Thanks again! :cheers:
Thanks, I was going to be using a 7qt pan with a baffle, tray and scraper, so if need be I can do soemthing different and modify the pan. I just don't want the bottom end of my motor coming apart!
That is the rear cap plate I was thinking about, I may just try to dig up a set of steel caps, or possibly just go splayed, just getting stretched thin, college, car, running my business, plus girlfriend makes things tough alll over :) hehehe Thanks again! :cheers:
Le Mans Master
Joined: Mar 1999
Posts: 6,744
Likes: 1
From: delmont pa
Cruise-In I Veteran
Cruise-In II Veteran
Re: Do I need Splayed Main Caps? (VETDRMS)
there was acompany selling a 400 rear cap renforcement plate like i discribed but i do not remember who. try a google search.
Le Mans Master
Joined: Mar 1999
Posts: 6,744
Likes: 1
From: delmont pa
Cruise-In I Veteran
Cruise-In II Veteran
Re: Do I need Splayed Main Caps? (clem zahrobsky)
go to http://www.pro-gram.com for a complete listing of caps and renforcement straps :chevy
Race Director
Joined: Dec 1999
Posts: 16,945
Likes: 9
Re: Do I need Splayed Main Caps? (VETDRMS)
http://www.milodon.com has steel splayed caps
http://www.oliverperformance.com has them too
[Modified by Twin_Turbo, 12:53 PM 3/1/2003]
http://www.oliverperformance.com has them too
[Modified by Twin_Turbo, 12:53 PM 3/1/2003]
