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6800 rpm 421 SBC Combo

General engine tech -- Drag Racing to Circle Track

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n2omike
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6800 rpm 421 SBC Combo

Post by n2omike » Tue Jan 07, 2020 11:16 am

Helping a buddy piece together a 421 street/strip SBC combo. He likes the AFR 220 heads, as they can use standard rockers. He has a Dart block, good rotating assembly, carb, intake, headers, exhaust, etc. Main thing he is stuck on is the cam/valvetrain. He is open to solid flat tappet, hydraulic roller or solid roller.

The cool thing about the AFR 220 heads, is they come with lighter 8 mm beadlock valves, and can be ordered with small diameter, lightweight PAC springs for hydraulic roller cams.
AFR-8019*
Hydraulic Roller
Red or Pink Stripe
1.270 OD
.645 ID
155 lbs. @ 1.810
448 lbs. @ 1.160
Premium Grade Chrome Silicon
PAC Racing Springs
Dual Spring
1.080 450 .650 7000-7200


I'm liking this option in case a hydraulic roller is used.

As for specs, I'm thinking around 254/264 @ 0.050" with a 110 LSA... as he might hit it with some nitrous at some point.

Thoughts and ideas?
Thanks!

n2omike
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Re: 6800 rpm 421 SBC Combo

Post by n2omike » Tue Jan 07, 2020 11:51 am

Also, I've always used solid lifters. Is a person losing much on such an engine, going with hydraulics... and speaking of which, if we go this way, what is a nice set of lifters that will work well spinning up close to 7k rpm with a decent camshaft.

He's not against going solid flat tappet or solid roller if there's something to gain. I've always had great luck with SFT cams. Last one I spec'd for him was 20 years ago... 406 with AFR 210 heads and a Lunati 40136 SFT (249/259 106 LSA). Ran 7.0's in a street '69 camaro back then. Has a new part number now. 30120936

But, nowadays the HR's have had a lot of time for development... With a GOOD set of lifters that won't collapse under pressure, and lightweight valvetrain, I think they could be a good choice. I'm just not experienced with HR setups... so experienced input is appreciated.

Thanks

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Re: 6800 rpm 421 SBC Combo

Post by prairiehotrodder » Tue Jan 07, 2020 12:00 pm

i would bite the bullet and go with bigger heads. I also have a friend that has a 423 SBC and we used AFR 227's which require offset lifters and T&D shaft rockers. They are good heads but now he wishes he had gone bigger. I believe Brodix makes a 233 head that uses standard valvetrain.

EDIT: sorry i see now that this is street / strip. I was thinking drag race.
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Re: 6800 rpm 421 SBC Combo

Post by mag2555 » Tue Jan 07, 2020 12:35 pm

If your buddy is looking for 650 hp he should have no problem doing that at least head with a roller Cam.

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Re: 6800 rpm 421 SBC Combo

Post by Orr89rocz » Tue Jan 07, 2020 12:38 pm

Afr 220 406-421 sbc is a tried and true street combo with hyd roller. I like your plans. Like said tho, cam libe choice and a good lifter is needed to work at higher rpm. May need more spring pressure than 155, shim to 175-180 would work depending what lobe lift is available before bind

I ran those pac spring afr195’s to 7000 in a 383 sbc. They work good.

I’ve also ran a .640” 246 deg cam in a 400” turbo combo to 7200 using a different pac 1371 spring at 180’s lb seat on morel 4602 lifters

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Re: 6800 rpm 421 SBC Combo

Post by CamKing » Tue Jan 07, 2020 1:01 pm

HR Cam# SBC, HR78390-80390-112
251/258 @.050"
.390"/.390" Lobe Lift
112 LSA
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n2omike
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Re: 6800 rpm 421 SBC Combo

Post by n2omike » Tue Jan 07, 2020 1:43 pm

CamKing wrote:
Tue Jan 07, 2020 1:01 pm
HR Cam# SBC, HR78390-80390-112
251/258 @.050"
.390"/.390" Lobe Lift
112 LSA
Nitrous will be between 200-300 hp.
I'm thinking this would be best with a 1.6 or 1.65 rocker?

lift with 1.5 = 0.585
lift with 1.6 = 0.624
lift with 1.65 = 0.6435

He has 1.5 rockers, but will likely sell them and buy something else.

Mike or anyone have specific recommendations on lifters for this application?

I sent you an email a couple days ago in regards to the SFT 'Gasser' cam I ordered from you... about the importance of the EDM lifters, the size of their oiling hole, and possibly adding them to the order.

Thanks!

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Re: 6800 rpm 421 SBC Combo

Post by BLOCKMAN » Tue Jan 07, 2020 2:08 pm

I would stay with the solid roller an those heads are basically all done around 6400 push rod pinch are is to tight and the port goes into sonic.

This combo has been duplicated many times with the same dyno results makes a ton of torque.

https://www.chevelles.com/forums/13-per ... sults.html

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Re: 6800 rpm 421 SBC Combo

Post by Gregory » Tue Jan 07, 2020 2:54 pm

n2omike wrote:
Tue Jan 07, 2020 11:16 am
Helping a buddy piece together a 421 street/strip SBC combo. He likes the AFR 220 heads, as they can use standard rockers. He has a Dart block, good rotating assembly, carb, intake, headers, exhaust, etc. Main thing he is stuck on is the cam/valvetrain. He is open to solid flat tappet, hydraulic roller or solid roller.

The cool thing about the AFR 220 heads, is they come with lighter 8 mm beadlock valves, and can be ordered with small diameter, lightweight PAC springs for hydraulic roller cams.
AFR-8019*
Hydraulic Roller
Red or Pink Stripe
1.270 OD
.645 ID
155 lbs. @ 1.810
448 lbs. @ 1.160
Premium Grade Chrome Silicon
PAC Racing Springs
Dual Spring
1.080 450 .650 7000-7200


I'm liking this option in case a hydraulic roller is used.

As for specs, I'm thinking around 254/264 @ 0.050" with a 110 LSA... as he might hit it with some nitrous at some point.

Thoughts and ideas?
Thanks!
Ran those springs with 220 AFR heads on my EFI HRC Morel lifters 408 SBC with a rev kit with peak power(600-615 HP) at 6,600/6,700 and ran it on the dyno many times to 7,200 with out any sign of valve train instability. I should have taken it a little higher.

n2omike
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Re: 6800 rpm 421 SBC Combo

Post by n2omike » Wed Jan 08, 2020 8:02 am

BLOCKMAN wrote:
Tue Jan 07, 2020 2:08 pm
I would stay with the solid roller an those heads are basically all done around 6400 push rod pinch are is to tight and the port goes into sonic.

This combo has been duplicated many times with the same dyno results makes a ton of torque.

https://www.chevelles.com/forums/13-per ... sults.html
That's a great combo! Only thing, is he wants to be able to use 200-300 worth of nitrous at some point... and the cam doesn't seem too nitrous friendly. Have you sprayed an engine with that cam? (259/263 SR 108 Lobe sep .626 lift.)

If he does decide to go hydraulic roller, any recommendations on lifters that won't collapse and lose lift under spring pressure... and still turn close to 7k rpm? What are you guys having the best luck with? Or is it a moot point, and you lose too much compared to a solid at this rpm range?

Thanks!

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Re: 6800 rpm 421 SBC Combo

Post by BLOCKMAN » Wed Jan 08, 2020 9:39 am

n2omike wrote:
Wed Jan 08, 2020 8:02 am
BLOCKMAN wrote:
Tue Jan 07, 2020 2:08 pm
I would stay with the solid roller an those heads are basically all done around 6400 push rod pinch are is to tight and the port goes into sonic.

This combo has been duplicated many times with the same dyno results makes a ton of torque.

https://www.chevelles.com/forums/13-per ... sults.html
That's a great combo! Only thing, is he wants to be able to use 200-300 worth of nitrous at some point... and the cam doesn't seem too nitrous friendly. Have you sprayed an engine with that cam? (259/263 SR 108 Lobe sep .626 lift.)

If he does decide to go hydraulic roller, any recommendations on lifters that won't collapse and lose lift under spring pressure... and still turn close to 7k rpm? What are you guys having the best luck with? Or is it a moot point, and you lose too much compared to a solid at this rpm range?

Thanks!
Any of the 421's that I have built of customers have built have not bee sprayed and that would be because of the ring pack location and Mahle pistons along with the cam in not NO2 friendly.

If I was going to build a HYD roller engine I would go to the Johnson Roller lifters those are very quite and you can adjust them as a anti pump up lifter and no problem.

Going from solid roller springs to Hyd roller springs is not cheap as I did that last year with the 427 SBF but its what the customer wanted. Minus .050 locks, retainers and spring cups instead of stacking up shims.

I would have to say the OP must be using the AFR 1066 heads I actually am working on the same build in the link but going to the AFR 1112 heads with shaft rockers and I am making an intake change as well and see how this engine does on the dyno just for an A to B test.

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Re: 6800 rpm 421 SBC Combo

Post by n2omike » Wed Jan 08, 2020 9:58 am

BLOCKMAN wrote:
Wed Jan 08, 2020 9:39 am

If I was going to build a HYD roller engine I would go to the Johnson Roller lifters those are very quite and you can adjust them as a anti pump up lifter and no problem.

Going from solid roller springs to Hyd roller springs is not cheap as I did that last year with the 427 SBF but its what the customer wanted. Minus .050 locks, retainers and spring cups instead of stacking up shims.
Thanks for the advice.
And, how do you adjust the lifters as 'anti pump up'? I read about where you adjust them with only 1/4 turn of preload... and also where you adjust them to where they are pretty much fully collapsed.

As for the HR springs being expensive, the small diameter PAC springs are a $77 upgrade straight from AFR over the springs that come stock on the 220 heads... which makes the HR cam a very affordable option.

He was also asking about Pro-Filer heads. You guys have any experience with those?

Thanks!

The springs again:
AFR-8019*
Hydraulic Roller
Red or Pink Stripe
1.270 OD
.645 ID
155 lbs. @ 1.810
448 lbs. @ 1.160
Premium Grade Chrome Silicon
PAC Racing Springs
Dual Spring
1.080 450 .650 7000-7200

BLOCKMAN
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Re: 6800 rpm 421 SBC Combo

Post by BLOCKMAN » Wed Jan 08, 2020 10:08 am

n2omike wrote:
Wed Jan 08, 2020 9:58 am
BLOCKMAN wrote:
Wed Jan 08, 2020 9:39 am

If I was going to build a HYD roller engine I would go to the Johnson Roller lifters those are very quite and you can adjust them as a anti pump up lifter and no problem.

Going from solid roller springs to Hyd roller springs is not cheap as I did that last year with the 427 SBF but its what the customer wanted. Minus .050 locks, retainers and spring cups instead of stacking up shims.
Thanks for the advice.
And, how do you adjust the lifters as 'anti pump up'? I read about where you adjust them with only 1/4 turn of preload... and also where you adjust them to where they are pretty much fully collapsed.

As for the HR springs being expensive, the small diameter PAC springs are a $77 upgrade straight from AFR over the springs that come stock on the 220 heads... which makes the HR cam a very affordable option.

He was also asking about Pro-Filer heads. You guys have any experience with those?

Thanks!

The springs again:
AFR-8019*
Hydraulic Roller
Red or Pink Stripe
1.270 OD
.645 ID
155 lbs. @ 1.810
448 lbs. @ 1.160
Premium Grade Chrome Silicon
PAC Racing Springs
Dual Spring
1.080 450 .650 7000-7200
Don't know what happened to my post........

I adjust 1/8 down from zero seems to have worked for years with no problem.

The springs that come on the heads the installed height I believe is 1.950 and your springs are 1.810 your going to need .140 of stacked shims. I went through this with a 427 SBF with the AFR 220 heads, I went to titanium retainers Minus .050 locks and thicker spring cups and it was not cheap. I could have stacked up the shims but it looks better with out doing that.

Have not seen any of the Pro filer heads as of yet.
Last edited by BLOCKMAN on Wed Jan 08, 2020 10:57 am, edited 1 time in total.

n2omike
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Re: 6800 rpm 421 SBC Combo

Post by n2omike » Wed Jan 08, 2020 10:33 am

BLOCKMAN wrote:
Wed Jan 08, 2020 10:08 am
n2omike wrote:
Wed Jan 08, 2020 9:58 am
BLOCKMAN wrote:
Wed Jan 08, 2020 9:39 am

If I was going to build a HYD roller engine I would go to the Johnson Roller lifters those are very quite and you can adjust them as a anti pump up lifter and no problem.

Going from solid roller springs to Hyd roller springs is not cheap as I did that last year with the 427 SBF but its what the customer wanted. Minus .050 locks, retainers and spring cups instead of stacking up shims.
Thanks for the advice.
And, how do you adjust the lifters as 'anti pump up'? I read about where you adjust them with only 1/4 turn of preload... and also where you adjust them to where they are pretty much fully collapsed.

As for the HR springs being expensive, the small diameter PAC springs are a $77 upgrade straight from AFR over the springs that come stock on the 220 heads... which makes the HR cam a very affordable option.

He was also asking about Pro-Filer heads. You guys have any experience with those?

Thanks!

The springs again:
AFR-8019*
Hydraulic Roller
Red or Pink Stripe
1.270 OD
.645 ID
155 lbs. @ 1.810
448 lbs. @ 1.160
Premium Grade Chrome Silicon
PAC Racing Springs
Dual Spring
1.080 450 .650 7000-7200
Did you reply? As I don't see where anything new was posted... Maybe something screwed up.
Thanks!

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Re: 6800 rpm 421 SBC Combo

Post by Orr89rocz » Wed Jan 08, 2020 11:00 am

I ran morel 4602 lifters but guys are complaining they are noisey. Mine werent really. An aggressive hyd roller usually has a sewing machine sound anyway. Good lifter bore clearance/machining is necessary either way and there are reports that morel lifters like certain oils better than others. Heard good about johnsons too tho

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