273 adjustable with roller cam?

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vje55

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Has anyone used the 273 adjustable rocker gear with a solid roller cam? I have a 340 flat tappet, smog heads ported 2.05/1.60 with 273 adjustable rockers, TRW etc. Can I use all this with a solid roller cam? I know that I will have to get new pushrods, but has anyone done this? Can I buy the adjusters for these to use ball to ball pushrods?
 
Not sure what the max spring pressure the 273 rockers can take is, but I'll bet a fairly mild roller would require more.
 
I do know the Crane iron rockers break around the rocker shaft, running a voodoo 63004, set up to the gnats ***. I think the stock pieces are stronger though, but heavy.
 
A .400 lift roller cam, no problem.

A .700+ lift roller cam, no.

They are pretty tough rockers.
 
I though I remembered the 273's being stronger than the 340 TA rockers..one was forged and one was cast? Rollers are usually pretty stiff sprung, dont know.
 
We never used the 273 ductile iron rocker arms on a roller cam motor.plenty of solid & hydraulic lift flat tappets worked just fine with the 273 rocker arms though. But we have without problems used the ductile iron W2 (offset) rocker arms/pedistals with a solid lift roller cam .640" (small roller) in (w2 340 motor).. in a dirt modified, for years actually, with no problems what so ever. .640" is a small solid roller though, we were turning the motor an honest 8000.never any problems.

I'm betting you could get away with it with a small roller...my 2c

edit: if i was running a roller cam to begin with i'd go with a good set of rocker arms though.. contrary to what i've said about the w2 stuff, we would have aswell but a good set of roller rockers for w2s are very costly... and ours worked just fine.
 
Recommendations for roller cam around the 600-620 lift, kit preferably....
 
I'm not arguing about it, but what do you think racers ran back before roller rockers were available? You bet the stock 273 rockers have seen .650 lift. Probably didn't endure it real long. But rest assured races were won with them. Just go back and read crackedback's post. There's your gospel right there. Although I would add I wouldn't be afraid to run them on a .550 lift roller. I think they'd hold up good. Specially if you have them bushed.
 
crackedback said:
A .400 lift roller cam, no problem.

A .700+ lift roller cam, no.

They are pretty tough rockers.
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i think this is accurate my first 3 seasons of circle track racing was on a very lean budget. i use a crower roller (bought it used) with .618 lift on ported 340 heads and 273 rockers. i never broke one of them .they are great strong pieces i ran the motor up to 7800 rpms and tried to stay 7500. there were 18 races a year i made every one of them 2 30 min practice sessions. trophy dash on occasion qualifying laps, 8 lap heat races, 30 lap main. every lap the engine would hit peak rpm twice. the point is do the math,i never broke one. but the thing that makes me say use different rocker is that with a aggressive roller cam the guides were wasted. a roller rocker wont do this. and if its a daily on the street you should think about this. i do know about saving money and racing and its hard to do. and these rocker are ready for the job.
 
Don't be surprised to see 1.43-1.45 ratios unless they are corrected.

Depending on spring pressures, .600 lift would be about the area I'd stop considering them. Consider that a .600 lift cam in a SB mopar isn't going be be anywhere near that actual number at the valve with the poor pushrod angles and iron rocker ratios.
 
Rob, no smartass meant....but how would you "correct" them?
 
You run a real roller cam with over .600 lift and you will have rocker arm geometry issues, not to mention the valve retainers hitting the insides of the rocker arm. The stock 273 stuff was designed for low lifts for thousands of miles with lots of spring retainer to rocker clearance. You can spend lots of money trying to make them work or you can spend less money buying the right pieces the first time. Talk to you cam maker. To 'fix' them you'd have to have someone bush them in the right spot to correct the ratio and them grind the heck out of the material under the fulcrum for spring retainer clearance, and maybe weld new material on the tops of the fulcrum to compensate for the strength lost when grinding them. Look at a good aftermarket aluminum roller rocker for a small block and I'll bet you see a half moon scooped out of the undersides of the rockers for retainer clearance.
 
You have to bush them. Once you do that you might as well spend money on a different rocker unless rules require you to run a factory rocker assembly.

Like Wall mentions, you get into other issues using them with high lifts.

I've clearanced a bunch of aluminum roller rockers to clear springs and retainers, so that solution isn't always a bargain either.
 
crackedback said:
You have to bush them. Once you do that you might as well spend money on a different rocker unless rules require you to run a factory rocker assembly.

Like Wall mentions, you get into other issues using them with high lifts.

I've clearanced a bunch of aluminum roller rockers to clear springs and retainers, so that solution isn't always a bargain either.
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I see, so then you're saying to actually *move* the shaft hole to correct the ratio, right?
 
Thanks guys, ok, after market rocker,,,,,,,,,,,,,what is a good kit/combo for my 340, remembering, smog heads heavily ported (will have them flowed for the cam to ensure they are up to it) 2.05/1.60, trw's 040 on scat rods, oil mod already done. Current cam, custom crow solid 247/255 @ 050 with around 570 lift, comp is 10.2:1, springs are 110 on the seat, 310 on the nose (I think).......so????????????? Thinkin around 600/620 solid roller jobby as it is for my circuit car that will spin fairly high, anyone had a combo/kit (roller cam and lifters, springs) they've bought and used so I will know it is a fairly proven affair?
 

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Nice car! As for your question,you are on unknown ground,be careful.If you drive this on the street, ante up buy a nice set of rollers.I worked in a speed shop,all heads got fit with K lines(google),and 21-4n valves.This was to offset rapid guide wear.Most cam grinders run a reduced base circle cam,because Chevy valvetrain can adjust(sort of) for it.
 
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