Can I move up to 1.6 ration roller tipped rockers in my 84 lg4 without performing any upgrades or mods to the rest of the valvetrain. I'd like to get more out of my pitifully lacking cam profile and this sounds like an easy bolt on. Not interested in doing a cam swap as i'll hopefully be dropping a 350 in this summer. Thanks

 

I've heard of people getting away with this. However, you're supposed to elongate the pushrod slots in the heads, or the pushrods can have interference with the slots. With the relatively low lift of a stock cam, you might be able to get away with it though.



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89RS w/350 TPI; 69RS/SS w/450 HP 350/Muncie 4-Speed "Too weird to live, too rare to die."

 

Well that sounds kinda scary. Hard to believe I spelled ratio as ration. Maybe I'll just go for the 1.5's with the roller tips. I have to take the valve covers off to adjust the stock ones so I figured i'd replace them while the covers are off. Cheers.

 

I swapped in 1.6 roller tipped rockers into my 305, when I had it, without having to change anything. I did use harder pushrods tho. at the time it was a 92 305tbi.

 

The odds in my personal experience with small block heads in general is about 50-50 you'll need to elongate the slot. Sometimes you get lucky. They tend to rub at zero lift as opposed to max lift; so sometimes you can get around it with longer pushrods.

Comp Cams sells a little tool they call the "Louis Tool" for $30 or $35. It's basically a drill bushing that positions the bit correctly for a perfect elongation. You can't really do it with the heads on though, unless you are willing to risk getting chips in the crankcase.

IMHO 1.6 rockers on the stock LG4 cam isn't worth the trouble; the cam has too little duration too, so the extra lift doesn't do much good. The best thing to do to the LG4 first is the exhaust, from heads to street, replace it with something big. Get L98 or L69 headers and cat-back and a high-flow cat if you get TES or SLP, NOT LG4. The next big restriction is the cam itself. Get that little weenie POS out of there. People say the Comp XE262H runs real strong in that motor.

The 1.5 roller-tip rockers can make a significant difference in almost any motor, just from getting rid of the stock sheet metal crap. If you ever get the chance to watch your valve train with a strobe light you'd be astounded how much they bend. Also, if you measure the actual ratio of stock rockers, you'll find they're very inconsistent; some of them are down in the 1.3x range, and hardly any are above 1.45. And that's theoretical, before taking into account the lost motion from them bending. The design valve lift in the LG4 is less than .400, and I'd bet money you don't get .360" out of the stock valve train.

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"So many Mustangs, so little time..."

 

That makes sense. Don't intend to do much more "hopping up" on this 150,000 mile lg4. Just want to keep her running until I can get the 350 swapped in.I have already done the exhaust/induction/chip/and ignition bit with it. I will probably gain a little bit more by swapping in the new 1.5's just do to the fact of consistency across the board.