Best headand cam combo for 421 SBC
 

I am building a 421 SBC and was wondering if u guys could could give me some help on the best heads and cam to use in it. I would like to get around 550 HP. out of it but i dont know for sure if thats a resonable number to look for and still keep it streetable? Would like to run aluminum heads and HYD.roller cam.Any ideas or thots are appreciated thanks.

Re: Best headand cam combo for 421 SBC
 

very possible with cashola ,how many bones do you want to give up ,cam i would like to introduce you to lunati cams
http://www.lunatipower.com/
heads i would go with bare set from enginekits and build them up with manley valves and pushrods ,or have george build them up here the 355 i built long block came out 2200
theres alot of factors ,torque ,transmission ,rear end ,what induction going to use ,blower ,turbo,nos ,

Re: Best headand cam combo for 421 SBC
 

For 420+ normally aspirated inches you want at least a 220cc head. Problem is most will require a offset rocker. Starts eating into the budget pretty heavy.

Heads $1400,
Crower offset shaft rocker around $900
custom cam to get the most lift you can get in the combination you have.. around $300


For getting exactly what you pay for, AFR is a phonenominal option. I do believe they are the ONLY one to guarentee flow to be within 1% of advertised. I've had 4 sets, 2 saw the flow bench and were within 5cfm ,, and one was MORE than advertised. The 220 eliminator would serve you well for the big inch sbc running under 6500 (which will be your limit with a hydraulic roller anyways) . Be cautious of getting just any large runner sbc head. Some have absolutely TERRIBLE port volocity and would mot make a street friendly motor. The right head for the right job :)

Wanting to be more serious, ,, well it's only money :)

Re: Best headand cam combo for 421 SBC
 

Thanks for the info. In your opinion then Marv do you think HYD roller is the best choice or would something else be better suited. The truck will probably only be driven about 300 to 500 miles a year at most.And is 550HP attainable out of something like this.Thanks again.

Re: Best headand cam combo for 421 SBC
 

Marv,

Do you know the diameter of a stock SBC lifter? I'm wondering how close they are to LS lifters. I'd be curious to know also how the oil galleys look in comparision. If one could find a way to use a Hyd LS lifter, the CTS-V or LS7 lifter has been shown to work all they way up to 8,200rpm in the 24 hour CTS-V races. Obviously you need to be creative for oil control.

I know we have discussed Hyd lifters and their limints before, but I know from experience that the LS lifter works past 6,500. Even a bone stock LS1 lifter from 98-02. I had a set in my old motor spinning to 7,400. Even made a few dyno pulls to 7,800 with it.

Re: Best headand cam combo for 421 SBC
 

I think there the same diameter (sbc is .842) but the height may be a problem?. I'd have to mic the oil hole for sure but a set of old Speedpros with a horizontal link bar are every bit of 3" tall. Oil hole I bet is less than 1" up from axle (I have some in the shop I'll mic tomorrow if you have an LS to compare) I wonder if lifter spacing is issue, or what? The part numbers list specific for Gen II sbc, and another # specific for LS motors. <shrugs>

Jay Allen said the cam he designed for my Camino would be good to 7000+, but the spring pressures he wanted to get there were well over 400psi on the nose. I just don't see beating up on a hydraulic roller like that. If you need that kind of RPM just put a solid in it and be done with it. I know Shaun,, old dog syndrome!!

Most all SBC Hydraulic roller cams you find listed in the cam companies listings call a low rpm limit. i.e a comp XE with 300/306° advertised with a advertised range of 3200-6200 That's patethetic isn't it! A heck of a lot of duration for only 6200!

http://www.summitracing.com/parts/CCA-12-444-8/

Evan ,, IMO... just depends on what your looking for. You can hit your 550 target EASILY with a hydraulic roller. And there is without a doubt a lot more to be had with a solid roller, more compression, MORE MORE MORE,,, BLA BLA BLA. With a good shaft rocker setup, and building the valve train light and durable, you can run a solid roller on the street (but I'd definately use a Morel / Isky lifter with HIPPO option). Just depends on what you willing to do/tolerate in the quest for power.

I know the AFR literature says the 220's will accept 'standard' sbc valve train components. (as do many large port heads) but ask around and youll find most use a shaft rocker system to build it 'right' . AFR, Dart and all will say 'accepts',, but talk to them and see what they 'recomend'. Your investing a lot, do it right the first time may kick the budgets a$$, but you know in the long run it's the smart money.

Again,, all just my 2¢

Re: Best headand cam combo for 421 SBC
 

Thanks Marv guess i might have to dip into what ive been saving a little deeper.

Re: Best headand cam combo for 421 SBC
 

Marv,

I agree that is a lot of duration for that rpm, but keep in mind a hyd cam is also rated differently than a solid. Hyd generally uses .006" lift for the total duration points where a solid often uses .020". The cam in my truck right now is a solid roller grind but I run hyd lifters on it. I forget exactly how much duration got added to the deal (I can look when I get home), but it was somewhere around 20* for each lobe.

There are pros and cons for both cams. The added duration of a hyd roller generally loses you some bottom end and driveability, but gains you a more "maintainence free" motor. I know I'm not telling you anything new here.

Let's talk spring pressures on a hyd cam for a moment.
What makes running 400lbs on a solid ok but not for a hyd? Once the hyd lifter is supplied oil, the liquid inside is uncompressable. The only area that I can see high spring pressures being a big issue, the possible side loading a hyd lifter could have since it does not have any lash (right as the lifter is accelerated). Maybe on start up to, from lifter bleed down, until oil pressure is up.

The last is something that I do here with my motor every time I fire it after sitting for a few days. But I'm running well over 400lbs on the hyd lifters.

Re: Best headand cam combo for 421 SBC
 

Just an FYI, the LS/SBC lifter bore diameter is the same, but the lifter bore spacing is wider on the LS than the SBC.....so you cannot interchange link bar style lifters.

Re: Best headand cam combo for 421 SBC
 

Do you know, is it 'just' the lifter spacing? Is the oil port in the same place on both? It would make sense if they were using the lifter diameter to make the things 'interchangable" (except for the link bar)

Re: Best headand cam combo for 421 SBC
 

Makes me wonder if the newer Comp LS link bar hyd lifters would work with different link bars. http://www.summitracing.com/parts/CCA-15956-16/

Re: Best headand cam combo for 421 SBC
 

If you only drive it 500 miles a year, put a solid roller in and forget about it. I am running a solid roller in the camaro, and I drive it around 500-1000 miles a year. I run the crane horizontal bar solid roller lifters. I am running 230# on the seat. Not sure on open pressure IIRC the springs maxed out a 500 or 600# tester before I was at open height. Its been too long.

I set the lash when I built the motor and haven't had to adjust it since. Its been together for 4 years since the last tear down. Just make sure and run a stud girdle.


600-650 should be easy to make depending on what stall you want to run and still be easily driveable.

Lynn

Re: Best headand cam combo for 421 SBC
 

I've been running a solid roller in my truck for about 1-1/2 years, and about 3000 miles so far with no problems at all. I run a Comp cam billet core, Isky Red-Zone E-Z roll lifters, and Jesel Sportsman shaft rockers,with Manton push rods. Like Marv said, you gotta use good parts if you want to run a mechanical roller, but they make power.

Re: Best headand cam combo for 421 SBC
 

Re: Best headand cam combo for 421 SBC
 

he aint too bad at head work :uhmk: :ito: :devil:

Re: Best headand cam combo for 421 SBC
 

Got any pics of the build?

Re: Best headand cam combo for 421 SBC
 

The LS7 hydraulic roller lifter will go in place if the LT1 or vortec roller lifter and is a good upgrade . All the other haerdware needs to stay LT1 or vortec style

Re: Best headand cam combo for 421 SBC
 

If you can find some splayed valve stuff from someone you can trust it will be impressive on the bigger inch engine. Minimal driving and a roller , I would not be too worried. You cant get on the power of a splayed valve or even a SB2 head. There used to be some good deals on used SB2 nascar heads complete. Just something to think about, it way cost some more but there are great deals on the used small block stuff that will make alot of power. If you want a cast intake on the splayed valve head you can get a Chrysler intake to work. LOL just grind off the penta star.

Re: Best headand cam combo for 421 SBC
 

You got several guys here that gave you great info.

I dont get much time to get on here.. however I am building a 407 SBC right now.

I build custom HD for a living , and the same questions get asked for these as well. Nothing more than a air pump plain and simple.

I see that when you start wanting a hp goal that the street side of the kit goeas to the way side. A 450 hp small block is a fun engine on the street. At the track there will always be guys that are faster and have more.

If the truck is really going to be running on the street then build it for that 80%+ use factor. NOS is always a fun way to get power for the track % ( as none of us would EVER hit the button on the street LOL)

I am running RHS 220 heads, a howards retro roller cam ( HRS 110275-10) that is a very close copy to the XR 294. I looked at the 304 as well. But did not want to kill the street side of my truck. comp level will be 10.6-10.8 once we see where everything stacks up. 850 street demon carb, and I am happy that I will no longer have to run the valves after a hard day or two of driving. Something to be said about less up keep.

We run hyr rollers in all of these HD engines with seat pressure in the 180-220 range and 450-550 on the nose with cams in the 660 lift area, some where we bump from the 1.6 rocker to a 1.7 . These lifters are stock and they handle it all day long, RPM ranges up to 6500 is the norm. And a air cooled engine. SO it can be done.

Running a tko 600( .64 over for the super slab stuff) with a 3.91 gear on 27 inch tires
for the street.

Over all it will not make huge numbers but will be a stout street machine that I can hope in a drive any where in the us I want to go.

Having had many race cars and trucks I can tell you that I dont miss them. Too much work, and I dont have the time to be messing with them all the time.

Things are changing that is for sure you can buy a CTS car that will run 190 mph off the show room floor and have a heated steering wheel as well .:)

The new gt stang is a 200 mph car. You can have it all , as long as the budget is big.

Having said all of that, I can say from my stand point I made a few changes in my build from where I started. all to have better street use vs a dyno sheet. Its just a piece of paper nothing more.

You make all this power but can you then put it to the ground and hook it?? A big hp engine in a auto will the right convertor, a rear end to handle the power, and a set up to hook it. Beat plenty of rigs at the track that had me by well over 100/100 if you cannot put the power down and get the sled to move you get beat. Smoke shows are great but you dont need 550 hp to turn tires into a mass of rubber on the ground.

Ask SUPER he runs on a regular basis as well does Marv. DO it right the first time as I am doing over this go round. I have about 14 grand now into the two engines total, as the first went went south. I hate do overs and they cost you a ton of money.

Re: Best headand cam combo for 421 SBC
 

[QUOTE=GMR-PERFORMANCE;5132801]You got several guys here that gave you great info.

I dont get much time to get on here.. however I am building a 407 SBC right now.

I know this is an old thread I was just wondering how you head and cam combo worked out for your 407

and to the OP did he ever get his engine built and how did it work out??

Re: Best headand cam combo for 421 SBC
 

I feel people are too scared of solid cams these days.
My bike needs the valves set every 16,000 miles per the manual. I do it every 32,000 and have never had any of them too far out of spec to make me want to do it sooner. Its really not that difficult, and its easier on a truck with all the space we have under the hoods. My 388 is a solid flat tappet as well.

Re: Best headand cam combo for 421 SBC
 

I built a pump gas 10.5:1 400 for a buddy using AFR Eliminator 195 heads, and a mild Lunati hydraulic roller (243/251 duration .560/.565 lift). Its in his full weight, street driven S10 Blazer with 700R4 and 4.10 gears. He runs mid to high 11's on drag radials and regularly pulls the front wheels 6" off the ground. The engine is totally streetable and I would say it makes 500-550hp easily.

Re: Best headand cam combo for 421 SBC
 

Sorry when I saw this post originally I did not see the power you were looking for. 550 h.p. will not require a whole lot of cylinder head on 421 inches. A 220cc casting will be more than enough to get you there.

Re: Best headand cam combo for 421 SBC
 

You're going to need at least a 230 cc head to get it to really breathe. My 406 makes right around 600 with a 220 head, solid roller and 10.4 compression. Runs 10.50's in my 64 Nova.

While I drive it to the track and cruise it I wouldn't want it to be a daily driver. The cam really makes the engine roudy. It doesn't smooth out until about 2000 rpm. I also have an 8" converter.

Re: Best headand cam combo for 421 SBC
 

These numbers seem real . I have a 392 with AFR 220 , solid roller @ 13 to 1 . Mine made 648 and I run low 10's @2880.