need options
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Joined: Jan 2002
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From: Chesapeake Va
need options
I've got a virgin 400 sbc with two bolt mains, I'm going to have it punched out 30 thou. over and build a 406, I need a few options for the rest of the setup. I don't plan on boosting it any so I don't think I need forged pistons or anything, I need recommendations for cams, intakes, heads. I am already going to put on headers and the usual exhaust stuff, I would like to reuse my CC-dist. and CC-carb so I dont have any tranny problems (700R4), I know this will choke the crap out of the 406 but I want it street drivable.
I am also going to use the 5.7" rods and modified pistons.
oh, by the way, do they make roller lifters that will fit into the '73 400 block without any block mods.m I would like to use a roller cam and rockers.
I am also going to use the 5.7" rods and modified pistons.
oh, by the way, do they make roller lifters that will fit into the '73 400 block without any block mods.m I would like to use a roller cam and rockers.
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Joined: Aug 1999
Posts: 14,811
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From: Jackson County
sure you can use a aftermarket roller can in the 400 block. i believe you'd have a lot more power and a lot more tuneable engine combo if you didn't use the ccc distributor and carb ,unless you have to for e check.
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Joined: Oct 2001
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From: Ft. Worth, TX
Re: need options
Originally posted by 1986redbird
I would like to reuse my CC-dist. and CC-carb so I dont have any tranny problems (700R4), I know this will choke the crap out of the 406 but I want it street drivable.
I would like to reuse my CC-dist. and CC-carb so I dont have any tranny problems (700R4), I know this will choke the crap out of the 406 but I want it street drivable.
Supreme Member
Joined: Jul 1999
Posts: 18,457
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From: Loveland, OH, US
Car: 4
Engine: 6
Transmission: 5
Been there, done that, it didn't work very well at all. I highly recommend against it unless absolutely necessary for e-check reasons.
It has to do with how a carb meters fuel at idle. A carb's idle circuit allows an amount of fuel to flow that's proportional to vacuum. Problem is, if you put a motor with 33% more cubic inches under a given carb with the same vacucum, you'll have to make the carb meter 33% more fuel. But then, if you put a cam in the motor that reduces the vacuum, the carb meters even less fuel, and the problem gets just that much worse. It's not so much of a problem cruising or at WOT, but it's a witch with a capital B to get it to idle or run anywhere near idle speed without chugging, surging, dying at inopportune moments like turning into a parking place, etc. There's essentially no way to get at the tuning orifices in the carb for that. I finally got sick of generally poor driveability after a year or 2 of fighting the Q-Jet and went to a Holley. My gas mileage improved, and the car was all-around better behaved.
I ended up with a Holley 6211 carb (800 CFM man sec dbl pump spreadbore) and several different cams over the years. The best 2 cams I've had were a Comp XE274H, and a XR282HR. The roller cam really lit it up.
HEADS!!!! HEADS!!!! HEADS!!!! A 400 requires 33% more air at any given RPM than a 305 does, and 15% more than a 350. Heads that seem huge to a 350 will still be a bottleneck to a 400. Spend your money on heads! All else is a waste if you put garbage (like the stock 400 heads, 882 casting) back on it. I have a set of lovingly massaged 186 double-humps on mine, they're really not enough.
All you have to do to put a "retrofit" (i.e., properly designed) roller system into an older block, like the rest of us had all been doing for decades before the factories finally wised up, is to use link-bar type roller lifters, a cam button, and .400" shorter push rods (7.300"). With the XR282HR I ended up with + .150" over stock roller-length push rods, which was 7.450".
Intake choice is somewhat limited, if you want it to fit under a stock hood. Don't do the stupid thing and put a high-rise intake on it, then discover that the carb is like 3/4' from the hood, and stick a "drop base" open element POS breather on it. If you look carefully, you'll notice that with a typical breather of that sort, the breather lid clears the carb air horn by an inch or so. In other words, if you do as described, you will successfully accomplish the incredible feat of moving the restriction from just under the carb, to just above it.
With the XE274H, a Performer not RPM and a stock L69 dual-snorkel breather on my 400, it did 284 RWHP and 373 RW ft-lbs. The big block 1st gen Camaro with a Comp 302 cam, square port heads, big headers, big intake, etc. that was on the dyno right in front of me, did 313 RWHP and 330 RW ft. lbs. Hmmmmmm....... I think I know which car would have won the race, if we had raced...
Oh, and did I mention that you should get the best heads you can afford?
It has to do with how a carb meters fuel at idle. A carb's idle circuit allows an amount of fuel to flow that's proportional to vacuum. Problem is, if you put a motor with 33% more cubic inches under a given carb with the same vacucum, you'll have to make the carb meter 33% more fuel. But then, if you put a cam in the motor that reduces the vacuum, the carb meters even less fuel, and the problem gets just that much worse. It's not so much of a problem cruising or at WOT, but it's a witch with a capital B to get it to idle or run anywhere near idle speed without chugging, surging, dying at inopportune moments like turning into a parking place, etc. There's essentially no way to get at the tuning orifices in the carb for that. I finally got sick of generally poor driveability after a year or 2 of fighting the Q-Jet and went to a Holley. My gas mileage improved, and the car was all-around better behaved.
I ended up with a Holley 6211 carb (800 CFM man sec dbl pump spreadbore) and several different cams over the years. The best 2 cams I've had were a Comp XE274H, and a XR282HR. The roller cam really lit it up.
HEADS!!!! HEADS!!!! HEADS!!!! A 400 requires 33% more air at any given RPM than a 305 does, and 15% more than a 350. Heads that seem huge to a 350 will still be a bottleneck to a 400. Spend your money on heads! All else is a waste if you put garbage (like the stock 400 heads, 882 casting) back on it. I have a set of lovingly massaged 186 double-humps on mine, they're really not enough.
All you have to do to put a "retrofit" (i.e., properly designed) roller system into an older block, like the rest of us had all been doing for decades before the factories finally wised up, is to use link-bar type roller lifters, a cam button, and .400" shorter push rods (7.300"). With the XR282HR I ended up with + .150" over stock roller-length push rods, which was 7.450".
Intake choice is somewhat limited, if you want it to fit under a stock hood. Don't do the stupid thing and put a high-rise intake on it, then discover that the carb is like 3/4' from the hood, and stick a "drop base" open element POS breather on it. If you look carefully, you'll notice that with a typical breather of that sort, the breather lid clears the carb air horn by an inch or so. In other words, if you do as described, you will successfully accomplish the incredible feat of moving the restriction from just under the carb, to just above it.
With the XE274H, a Performer not RPM and a stock L69 dual-snorkel breather on my 400, it did 284 RWHP and 373 RW ft-lbs. The big block 1st gen Camaro with a Comp 302 cam, square port heads, big headers, big intake, etc. that was on the dyno right in front of me, did 313 RWHP and 330 RW ft. lbs. Hmmmmmm....... I think I know which car would have won the race, if we had raced...
Oh, and did I mention that you should get the best heads you can afford?
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