400 Build thread
06-10-2016, 03:35 PM
#1
400 Build thread
So the 355 in my 84 went belly up. I lost oil pressure (verified with mechancial gauge) and I have shiny's in the oil. It's already .040 and I'm not keen on going possibly .060 on a street motor. So i'm looking at building a 400sbc (something i've wanted from the beginning). LS motors aren't cheap up here, at least what I'm looking at for this build and I'm not keen on doing that swap just yet.
So here is what I'm looking at.
Dart SHP block (Going new, no old cores for sale here and with shipping and pep work, cost is comparable). (Getting a good discount compared to what summit offers from a local guy)
Scat forged rotating assembly (9.5:1 to 10.1:1) compression. Probably want closer to 9.5:1 for street purposes.
Lunati Cam .515in/.530ex lift, Advertized duration 270/278 219/227 @ .050 1800-5800 (Little on the small side but it's in my 350 currently and should be fine).
World Sportsman II heads (From current 350), 66cc chambers, 1.52 roller rockers, angle plug)
Edelbrock performer intake and CC Qjet on top of it all.
The last three items are because I am on a bit of a budget and can't afford $5000 for everything I want. It also leaves me room to improve later on.
Other mods, built 700R4, 2800 Stall Vigilante Converter, 3.73 Gears.
Just looking for thoughts and ideas.
So here is what I'm looking at.
Dart SHP block (Going new, no old cores for sale here and with shipping and pep work, cost is comparable). (Getting a good discount compared to what summit offers from a local guy)
Scat forged rotating assembly (9.5:1 to 10.1:1) compression. Probably want closer to 9.5:1 for street purposes.
Lunati Cam .515in/.530ex lift, Advertized duration 270/278 219/227 @ .050 1800-5800 (Little on the small side but it's in my 350 currently and should be fine).
World Sportsman II heads (From current 350), 66cc chambers, 1.52 roller rockers, angle plug)
Edelbrock performer intake and CC Qjet on top of it all.
The last three items are because I am on a bit of a budget and can't afford $5000 for everything I want. It also leaves me room to improve later on.
Other mods, built 700R4, 2800 Stall Vigilante Converter, 3.73 Gears.
Just looking for thoughts and ideas.
06-29-2016, 12:43 PM
#2
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Car: 82 Berlinetta/57 Bel Air
Engine: LS1/LQ4
Transmission: 4L60E/4L80E
Axle/Gears: 12B-3.73/9"-3.89
Sorry, missed this first time I read it. Thought it was just going to be a documentary... 
Those two don't seem compatible. The cam will act "smaller" in the larger engine, but power would still be higher with the larger engine. I assume this is flat tappet, meaning "relatively cheap". I'd go with new cam/lifters as "cheap" insurance. You could also get a grind more to your liking (although the CC carb won't like much more duration/overlap).
Kudos there.
With the typical 4-valve relief pistons, you're looking at around 11+:1 CR. Better get dished pistons. 15cc dish would give you 10:1 (assuming zero deck height, .040" compressed thickness head gaskets).
Have you considered the spreadbore Performer RPM? I know you said "budget", but that's a cost you can partially offset by selling what you've got. The spreadbore RPM doesn't have EGR provision, but that shouldn't pose a problem.
Have you considered the spreadbore Performer RPM? I know you said "budget", but that's a cost you can partially offset by selling what you've got. The spreadbore RPM doesn't have EGR provision, but that shouldn't pose a problem.
06-29-2016, 09:28 PM
#3
Re: 400 Build thread
Sorry, missed this first time I read it. Thought it was just going to be a documentary...
Those two don't seem compatible. The cam will act "smaller" in the larger engine, but power would still be higher with the larger engine. I assume this is flat tappet, meaning "relatively cheap". I'd go with new cam/lifters as "cheap" insurance. You could also get a grind more to your liking (although the CC carb won't like much more duration/overlap).
Kudos there.
With the typical 4-valve relief pistons, you're looking at around 11+:1 CR. Better get dished pistons. 15cc dish would give you 10:1 (assuming zero deck height, .040" compressed thickness head gaskets).
Have you considered the spreadbore Performer RPM? I know you said "budget", but that's a cost you can partially offset by selling what you've got. The spreadbore RPM doesn't have EGR provision, but that shouldn't pose a problem.
Those two don't seem compatible. The cam will act "smaller" in the larger engine, but power would still be higher with the larger engine. I assume this is flat tappet, meaning "relatively cheap". I'd go with new cam/lifters as "cheap" insurance. You could also get a grind more to your liking (although the CC carb won't like much more duration/overlap).
Kudos there.
With the typical 4-valve relief pistons, you're looking at around 11+:1 CR. Better get dished pistons. 15cc dish would give you 10:1 (assuming zero deck height, .040" compressed thickness head gaskets).
Have you considered the spreadbore Performer RPM? I know you said "budget", but that's a cost you can partially offset by selling what you've got. The spreadbore RPM doesn't have EGR provision, but that shouldn't pose a problem.
Thanks for the info Five7!
It still may be a documentary once I get going on it.
1. Dart SHP block will be set up for a roller cam.
2. My current Lunati Cam from my blowed up 355 is a roller cam.
3. I would re-use my World Sportsman II heads, Edelbrock Performer Intake and CC Qjet. The Performer RPM, from everything I Can find, will not fit under a stock firebird hood. It will also save me quite a bit of money. However I have a line on a TPIS 1206 port Miniram, Injectors, fuel rails and an Accell DFI Gen 7 with harness and wideband 02 set up for around $1500 total if i want it.
4. For Cam's, I could step up to this:
Advertised Duration (Int/Exh): 282/290
Duration @ .050 (Int/Exh): 231/239
Gross Valve Lift (Int/Exh): .535/.550
LSA/ICL: 110/106
Valve Lash (Int/Exh): Hyd/Hyd
RPM Range: 2400-6400
Includes: Cam Only
Part Number: 20080722
Previous Part Number: 60122
Or this:
Advertised Duration (Int/Exh): 294/302
Duration @ .050 (Int/Exh): 243/251
Gross Valve Lift (Int/Exh): .560/.565
LSA/ICL: 110/106
Valve Lash (Int/Exh): Hyd/Hyd
RPM Range: 2800-6800
Part Number: 20080723
Previous Part Number: 60123
Except that on the latter the RPM range is higher than I want for a street motor.
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