chcgobearsfan3

$220 1.7 Roller Rockers ( .397/.435) with LG4 cam (179/194)
$0-$50 Stock (081 or similar) heads, cleaned up, slightly milled, and 1.94 valves (though stock 1.84 are adequate)
$230 1.5" primary headers & Y & stock 2 1/4 back with better flowing muffler

Extra-- Dual snorkel, got mine on CL for $30
-- L69 chip, or advance base timing a few degrees


Is there any cheaper way to make ~50-60 hp and a fun, efficient, daily driver with typical, open 2.73s? This is around $10/hp,
based on a few different dyno programs, and should gain a couple mpg all around. Along with removing some weight,
(50-200 pounds, depending on budget, still fairly cheap) this could be a fun ride for the DD 305 people.

Thoughts/suggestions?

Stangski09

iTrader: (10)

Damn is that ever definition budget.

87350IROC

iTrader: (2)

I'd forget about the rockers if your budget is $500. Instead buy a much bigger cam.

chcgobearsfan3

Any after market cam is going to require machining for higher lift, I should've said budget and DIY for beginners. A longer duration cam could mean new rear gears depending on how big, or it might be a slug off the line. I was thinking more about the daily driver that wants both power and efficiency..not much track use, but great for off the line and cruising 80 @ 2000 RPM, but yeah that's another option. Lift is almost always more efficient than duration, though.

Saabster

iTrader: (2)

I too don't think the rockers are worth it. A LT1 or Ramjet cam would be much more useful even just with stock stamped rockers. Both of those have low enough lift that they shouldn't need any machining, though they will need new valve springs.

Atilla the Fun

No, you can run quite a bit more cam without machining. On a budget, forget the roller rockers and the larger intake valves.
Spend $75 on a good used 3.42:1 rear axle assembly from an '84-up V6/automatic F-car. That's the best bang-for-buck of all.
For a cam, the COMP High Energy 252 would be a good match, and not require any machining.

Atilla the Fun

Since he specified LG4 cam, his block is too old to use the GM roller cams.

Saabster

iTrader: (2)

^This, my stock LO3 is awesomely torque in third on the highway.

I missed that.

87WS6

iTrader: (1)

Unless its an 1987 LG4. Those were the only year the LG4 was offered with roller cams.

Atilla the Fun

You're right. Thanks for the catch.

chcgobearsfan3

It is an 87, it's not a roller, it has 081 heads.

3.42s take away from the fuel efficiency, I intended this for beginners that could easily do this on their own. It's a turd of a cam, but it's still going to be the most efficient and have the lowest torque peak for daily driving. I was thinking about ease of installation, for beginners, a 50 hp gain, a mpg or two increase, and an easy DIY job isn't all bad. A lot of people that come around are looking for mild upgrades for their 305s and don't know how or can't just take off the rear axle. At least, that's what I've seen.

The people that have been around would obviously do differently and steer clear of the 305 at that. :P

FWIW: My other 87 sc IS a roller and has 081 heads..

Question.. what are the cam specs for non-roller 87s vs roller 87s? Same as -86 I'm assuming?

Atilla the Fun

My best MPG combos never once included any LO3 or LG4 with a 2.73:1 axle. It can cruise that way, but it's not good. And in town, the 2.73 axle actually hurts your mpg. At least go 3.08:1. The rearend swap is nearly impossible to screw up, making it about the easiest mod possible. A better ratio rear axle assembly should usually be the first mod.
Non-roller cams can be used in roller blocks, but for newbs, best to use the roller lifters in a later block. Stepping up to the RamJet 350 cam is a very good choice.
If you found a combo you like, that works well for you, that's great, and I'll be happy for you. But declaring your combo the best, when you haven't tried literally dozens of others, would be folly.
Bolting 1.7:1 rockers on should work for LO3s, if you give it fresh but moderate springs, but is a no-no for non-roller cams and high-mileage springs. Too much probability of hurting something.

chcgobearsfan3

The easiest mod, really? Not once did I say it was the best, I also pointed out that people with know-how would do otherwise. If anyone is pushing, "my idea is the best," it's you. The 3.06 first gear negates needing anything lower than 2.73 for city driving. I said "budget" and "beginner" numerous times.. for all of the people that don't know if they have a roller block or not, for the 100s of posts asking how to make power with a 305. Easily done in a day for a beginner and you've got 50 extra horsepower and better efficiency. Again, "budget high torque 305 build for less than $500." It's not about having more than 200-some hp, it makes a crap stock engine a bit more fun to drive in the easiest way possible.

I'm not looking to argue, obviously it'd be more efficient to swap to a mild fuel injected LS block and a stick shift, but that's not what the post was about. Most of us have carb'd 305s and low budgets.

Doom86

Lots of holes in this idea. There's no need to re-invent the wheel here.

The first thing you need to do is replace the exhaust from the heads to the tail-pipe. There's your HP and MPG right there. After this you need to tune the secondaries on your Quadrajet. Also while you have the O2 sensor off you would be wise to convert to a heated sensor, these slow reacting LG4 computers have better authority of air/fuel mixture this way if you have headers. Once you've done this you need to check/adjust MCS dwell.

With these mods, your dual snorkel, and tune you would easily get 40-50hp with MPG also.

Where in the world are you going to get all that machine work done for $50? Try $250 then it seems more legit.

Atilla the Fun

I can speak with authority, I have tried literally dozens of combos. Notice how my hair is going gray.
2.73 times 3.06 is a rather poor 8.36:1. Can you drive that in town? of course. Is it good? Oh hell no!
Why make more power until you're taking best advantage of what power you have? Your thread here is advocating something that extensive experience says isn't wise. Changing a rear end is far easier than any cam swap.
Yes, the rearend is heavier than a cam. If you don't have muscles in your arms, get a come-along, a breaker bar and a roll-around mini floor jack. But it still requires less finesse than the cam, and less money.
You keep mentioning 50 horses and $500. On the dragstrip, that's worth 1/2 second, in theory.
The axle swap can be successfully completed for 1/5 that price, and going from 2.73:1 to 3.42:1 will return 4/10 of a second 9 times out of 10.
I did this exact swap as my forst mod to my '91 camaro RS LO3/autoi/2.73, which was averaging 23 mpg in combined driving. After the 3.42:1 and the speedo recal, I still averaged 23 mpg.
Go build your car your way, then try it my way. If you're fair and honest, you won't go back to your way. I'd stake my very soul on it.

built91Z28

I agree that a used rear axle would be the best starting point. No offense to anyone, but if you cant unbolt a few bolts and swap an entire axle (not talking about rebuilding), then you have no buisness swaping heads or setuping up a valvetrain.

Gallileo60

I went from 2.73 gears to 3.23, and did not loose any mileage as far as I can tell...If I lost any, it is not noticeable.Also came with disc brakes, and a posi..That was about 3, or 4 years ago.. Sure made the car a lot more fun to drive...Tried to put 1.6's on my roller motor, and it was no go, until I enlarge the area around the push rods...Good luck...Tom

el_muerte

A beginner is gonna do a cam swap, install roller rockers, get his heads milled and larger valves installed, and install headers, a Y-pipe, and a muffler in a day? maybe with the engine out of the car...

And hook me up with this place you're getting headers, y-pipe, and muffler for $230. 'Coz that's what I paid just for my headers, and they were cheap.

I'd replace the rockers in your list with a bigger cam and probably not suggest that these can all be accomplished in a day for your average backyard mechanic.