SBC 421 combo advice

General engine tech -- Drag Racing to Circle Track

Moderator: Team

redliner
Expert
Expert
Posts: 720
Joined: Sun Feb 26, 2012 4:07 pm

Re: SBC 421 combo advice

Post by redliner » Wed Jan 24, 2018 6:10 pm

MTENGINES wrote:
Wed Jan 10, 2018 6:11 pm
421SBC

11.7:1
23 degree heads hand ported
Single 950 4150
How much cam?

raynman1969
New Member
New Member
Posts: 21
Joined: Sun Jan 07, 2018 10:18 am

Re: SBC 421 combo advice

Post by raynman1969 » Fri Mar 30, 2018 5:40 pm

raynman1969 wrote:
Sun Jan 07, 2018 10:49 am
Looking for some combo advice for my build. Engine is going in a 1969 Camaro, auto trans turbo 400 3500-4000 stall approx. This will be street driven very little and drag raced. 3 7/8 stroke x 4.155 bore, flat top pistons looking to run 11 to 11.5 comp. when i was shopping for cylinder heads i was told the cam i purchased would not be correct for my engine. Cam specs 626 626 lift, 262/271 duration at .050 lsa 106 icl 102. I was looking at afr 220 or afr 235's, edelbrock cnc super victor with a holley 950xp. Lemons 1 7/8 headers. I need some advice on this cam, if it will not work nows the time to change before i complete the engine assembly and which heads would people recommend? I plan on running 100 octane on the street and 110 race gas on the strip. One last thing i have a nos kit with up to a 250 hp shot.
I went with the afr 220 and the lunati cam above. It was run on the dyno with 1 3/4 headers with 50/50 91 octane and 110 vp
You do not have the required permissions to view the files attached to this post.

raynman1969
New Member
New Member
Posts: 21
Joined: Sun Jan 07, 2018 10:18 am

Re: SBC 421 combo advice

Post by raynman1969 » Sat Mar 31, 2018 8:33 am

The cam seems to work , the goal was to be over 600 hp. We will have to get it in the car to see if the NOS will work. With straight 110 I should pick up a little.

wingnut
New Member
New Member
Posts: 11
Joined: Tue Apr 23, 2013 8:16 pm

Re: SBC 421 combo advice

Post by wingnut » Sat Apr 07, 2018 8:53 pm

Finished assembling my street strip 421 freshened bottom end had AFR 220s freshened went with different cam 257/263@ .050 .660intake .624 ext. 108 104 in.112 exh. Changed converter to9" 4500/4800 Old cam and car setup 253/256@.050 .573/.584 110 106 went 11.15 @122 mph pump gas and exhaust on 3200# gbody 350th 3500 con. Just fired on run stand tonight and it sounds pretty good

raynman1969
New Member
New Member
Posts: 21
Joined: Sun Jan 07, 2018 10:18 am

Re: SBC 421 combo advice

Post by raynman1969 » Sun Apr 08, 2018 10:53 am

what kind of performance should I expect from this combo, approx. 3300 lbs with driver, 4000 stall converter, 4.30 rear gear,turbo 400 transmission.
325/50/15 m/t street R radial tires. 614 hp at 6500 rpm, 575 ft lbs of torque at 5000.

wingnut
New Member
New Member
Posts: 11
Joined: Tue Apr 23, 2013 8:16 pm

Re: SBC 421 combo advice

Post by wingnut » Sun Apr 08, 2018 11:24 am

It will be a blast on the street as well as the track if you plan on running at the track. Waiting to see how my new combo works out hoping to get into the 10's with it was close with old combo

77cruiser
Guru
Guru
Posts: 1086
Joined: Fri Dec 29, 2006 10:32 pm
Location: I Falls MN
Contact:

Re: SBC 421 combo advice

Post by 77cruiser » Sun Apr 08, 2018 12:00 pm

raynman1969 wrote:
Sun Apr 08, 2018 10:53 am
what kind of performance should I expect from this combo, approx. 3300 lbs with driver, 4000 stall converter, 4.30 rear gear,turbo 400 transmission.
325/50/15 m/t street R radial tires. 614 hp at 6500 rpm, 575 ft lbs of torque at 5000.
10 flat if the car is set up right.
Jim

raynman1969
New Member
New Member
Posts: 21
Joined: Sun Jan 07, 2018 10:18 am

Re: SBC 421 combo advice

Post by raynman1969 » Sun Apr 08, 2018 7:23 pm

If I could run low tens with this combo i would be very satisfied.

rfoll
Guru
Guru
Posts: 2206
Joined: Mon Jan 11, 2010 12:44 pm
Location: St. Helens, OR

Re: SBC 421 combo advice

Post by rfoll » Mon Apr 09, 2018 11:03 am

I suspect you will need to put some good wrinkle wall slicks on it to run in the 10's.
So much to do, so little time...

User avatar
67RS502
Expert
Expert
Posts: 677
Joined: Wed Apr 20, 2005 12:57 pm
Location: Houston Tx.
Contact:

Re: SBC 421 combo advice

Post by 67RS502 » Tue Apr 10, 2018 4:12 pm

I would expect some low 10s, mid 10s if the car needs a bit of work, in decent DA.
67 camaro
girly rollers on pumpgas:
420 - 641hp BretBauerCam, 1.39, 9.79 @ 137.5
383 - 490hp 224/224, 1.56, 10.77 @ 124.6
502 - 626hp 252/263, 049s 1.44, 10.08 @ 132.7
62 Nova cruiser
383/200-4R/12-bolt w 373s
224/224 HR cam
1.57 10.97 @ 121.2

GARY C
Guru
Guru
Posts: 4623
Joined: Tue May 14, 2013 10:58 pm

Re: SBC 421 combo advice

Post by GARY C » Tue Apr 10, 2018 4:30 pm

rfoll wrote:
Mon Apr 09, 2018 11:03 am
I suspect you will need to put some good wrinkle wall slicks on it to run in the 10's.
Most people find the drag radial quicker than slicks due to less wasted motion.

rfoll
Guru
Guru
Posts: 2206
Joined: Mon Jan 11, 2010 12:44 pm
Location: St. Helens, OR

Re: SBC 421 combo advice

Post by rfoll » Wed Apr 11, 2018 10:21 am

"325/50/15 m/t street R radial tires" ... I don't believe this is a drag radial.
So much to do, so little time...

77cruiser
Guru
Guru
Posts: 1086
Joined: Fri Dec 29, 2006 10:32 pm
Location: I Falls MN
Contact:

Re: SBC 421 combo advice

Post by 77cruiser » Wed Apr 11, 2018 12:29 pm

DOT legal drag radial.
Jim

Post Reply