cheap HP
02-20-2015, 06:16 PM
#21
8th Gear
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Yes, that would be the first place I'd suggest looking as well. A deeper rear gear will increase torque multiplication at the rear tires across the board. However, if you're after a general purpose performance ratio, and not focused strictly on 1/8 or 1/4 mile ETs, IMHO it's tough to beat a 3.55. In any event, bear in mind the percentage difference between your current gear and the new one in question will directly determine the bang you'll get for this particular buck. For instance, stepping up from a 3.08 to a 3.55 will yield ~15% more torque multiplication while stepping up from a 3.36 to a 3.55 is only worth ~6% more at the same expense. So, do your maths.
Under the hood, assuming a healthy mill, I'd install a performance air filter, and super-tune the ignition system and carb, in that strict order. Upgrading the HEI's innards wouldn't be a bad call. However, I would NOT suggest swapping to a smaller aftermarket carb. They're not the easiest to deal with, but IMHO a well tuned Q-jet is better than any undersized aftermarket carb.
In future, other than headers and freer flowing exhaust system (and perhaps a better intake), I wouldn't bother with much else until you can afford to bump up your L48's meager compression ratio, even if only done by milling your existing heads (assuming they're not cracked). A 3-angle valve job would be worth considering if possible to budget in at this point.
It's easy to over-spend other people's money, but I do hope I've stayed within the more budget minded suggestions.
Under the hood, assuming a healthy mill, I'd install a performance air filter, and super-tune the ignition system and carb, in that strict order. Upgrading the HEI's innards wouldn't be a bad call. However, I would NOT suggest swapping to a smaller aftermarket carb. They're not the easiest to deal with, but IMHO a well tuned Q-jet is better than any undersized aftermarket carb.
In future, other than headers and freer flowing exhaust system (and perhaps a better intake), I wouldn't bother with much else until you can afford to bump up your L48's meager compression ratio, even if only done by milling your existing heads (assuming they're not cracked). A 3-angle valve job would be worth considering if possible to budget in at this point.
It's easy to over-spend other people's money, but I do hope I've stayed within the more budget minded suggestions.
02-20-2015, 10:36 PM
#22
Nam Labrat
Member Since: Sep 2013
Location: New Orleans Loo-z-anna
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Shorty headers(easy to install)......
1:6 stamped rocker arms(not the cheapies)......
machine work to heads (unless budget is a priority, then see below)
NEW HEAD GASKETS .035 thick(but ONLY if you have plenty of piston-to-valve-clearance.& they cost much less than machine work)....
re-tune the carb and timing.....
C.A.I......
3:36 differential gears (3:55's are good for acceleration/but 3:36's are also good for acceleration and for holding down rpm-s on the open road/slightly better mpg than 3:55).
02-23-2015, 06:10 PM
#23
what is 1.6 stamped rockers arms? and how can i tell if i can use a 0.35 gasket?
that the same for a 305?
And diff gears, how can i tell what i have now?
These should also help the OP as well as myself !
that the same for a 305?
And diff gears, how can i tell what i have now?
These should also help the OP as well as myself !
02-23-2015, 10:57 PM
#24
Le Mans Master
To check possible head gasket thickness options, you have to know how deep in the hole are your pistons from the deck. The aim being to achieve a quench of ~.045", if they're .025" in you could run .020" gaskets. CID wouldn't matter here.
Jack your rear tires off the ground, properly support your car on jack stands (never rely on a jack) and chock the fronts so it can't move. Put the trans out of gear (neutral for autos) and rotate the tires while noting how many times around it takes to turn the driveshaft 360*. Then round off your findings to match the nearest available ratio. Note that if the rears turn in opposite directions, your rear end is operating as an open diff, so this method isn't likely to work.
02-24-2015, 10:19 AM
#26
Racer
My suggestion is live with it till you can afford to replace the motor. If a new motor is in your future most of the money you spend on the 350 (not including gears) is going to be a waste.
I say save your money. Pretend you just got a new carb and pocket the cash, price out some headers and keep the money. Soon you will have enough to buy/build your motor.
And if you want cheap power then put a dry 50 or 75 shot of N2o in it.
I say save your money. Pretend you just got a new carb and pocket the cash, price out some headers and keep the money. Soon you will have enough to buy/build your motor.
And if you want cheap power then put a dry 50 or 75 shot of N2o in it.
02-27-2015, 06:37 AM
#28
Yes, that would be the first place I'd suggest looking as well. A deeper rear gear will increase torque multiplication at the rear tires across the board. However, if you're after a general purpose performance ratio, and not focused strictly on 1/8 or 1/4 mile ETs, IMHO it's tough to beat a 3.55. In any event, bear in mind the percentage difference between your current gear and the new one in question will directly determine the bang you'll get for this particular buck. For instance, stepping up from a 3.08 to a 3.55 will yield ~15% more torque multiplication while stepping up from a 3.36 to a 3.55 is only worth ~6% more at the same expense. So, do your maths.
Under the hood, assuming a healthy mill, I'd install a performance air filter, and super-tune the ignition system and carb, in that strict order. Upgrading the HEI's innards wouldn't be a bad call. However, I would NOT suggest swapping to a smaller aftermarket carb. They're not the easiest to deal with, but IMHO a well tuned Q-jet is better than any undersized aftermarket carb.
In future, other than headers and freer flowing exhaust system (and perhaps a better intake), I wouldn't bother with much else until you can afford to bump up your L48's meager compression ratio, even if only done by milling your existing heads (assuming they're not cracked). A 3-angle valve job would be worth considering if possible to budget in at this point.
It's easy to over-spend other people's money, but I do hope I've stayed within the more budget minded suggestions.
Under the hood, assuming a healthy mill, I'd install a performance air filter, and super-tune the ignition system and carb, in that strict order. Upgrading the HEI's innards wouldn't be a bad call. However, I would NOT suggest swapping to a smaller aftermarket carb. They're not the easiest to deal with, but IMHO a well tuned Q-jet is better than any undersized aftermarket carb.
In future, other than headers and freer flowing exhaust system (and perhaps a better intake), I wouldn't bother with much else until you can afford to bump up your L48's meager compression ratio, even if only done by milling your existing heads (assuming they're not cracked). A 3-angle valve job would be worth considering if possible to budget in at this point.
It's easy to over-spend other people's money, but I do hope I've stayed within the more budget minded suggestions.
1980 Positraction 3.07 ratio DANA
1979 Positraction 3.55 ratio OH
1979 Positraction 3.36 ratio OM
https://www.rockauto.com/catalog/x,c...79%2BCHEVROLET
So which parts do i buy? mine is leaking and has some play when pulling on the drivers half shaft so may as well fix it and change gears. Do the speedo gears need to be switched ? If yes how do you figure that out?
AS for rocker arms 1.6:1
https://www.rockauto.com/catalog/x,c...79%2BCHEVROLET
any suggestions ?
Thanks again, hope this helps OP and you dont mind some high jacking and adding of info
Last edited by R6n350GT; 02-27-2015 at 06:43 AM.
02-27-2015, 01:08 PM
#29
Recurve your distributor and spend money improving your very bad exhaust system. Your L/48 cam is a very low lift 4500 rpm cam. Don't need to spend money on a different intake to supply air to this rpm level. If your going to change cam and heads then consider a better intake manifold.
Aftermarket heads are slotted for extra push rod clearance needed to use 1.6 rockers. Your factory heads are not. 1.6 rockers will also put more strain on your lobes and lifters that are already old. Also your cam is 3.90/4.10 lift even adding a 1.6 is a very tiny help to this cam.
Spend money for a better stall converter if you have an auto not on 1.6 rockers.
Aftermarket heads are slotted for extra push rod clearance needed to use 1.6 rockers. Your factory heads are not. 1.6 rockers will also put more strain on your lobes and lifters that are already old. Also your cam is 3.90/4.10 lift even adding a 1.6 is a very tiny help to this cam.
Spend money for a better stall converter if you have an auto not on 1.6 rockers.
Last edited by Little Mouse; 02-27-2015 at 01:56 PM.
02-28-2015, 09:45 AM
#30
Not trying to be a kill joy to the thread but you said a limited budget. I assume you would like to have the most bank for your buck with limited money you can spend. Assuming your car has ended up dead stock and the typical 3.08 auto L/48 that most L/48 cars came with.
The recurve will cost you almost nothing you will feel the difference seat of the pants.
The next nice kick in the pants in cost would be a change to the converter not expensive.
The exhaust will cost you some and help a lot. But is a must have before you do any real mods to the engine.
1.6 rockers if you did do it you would never even feel the difference. These others you will feel the difference with each one.
Of course if you want to go into the engine or rear and start spending more money you can keep improving further.
The recurve will cost you almost nothing you will feel the difference seat of the pants.
The next nice kick in the pants in cost would be a change to the converter not expensive.
The exhaust will cost you some and help a lot. But is a must have before you do any real mods to the engine.
1.6 rockers if you did do it you would never even feel the difference. These others you will feel the difference with each one.
Of course if you want to go into the engine or rear and start spending more money you can keep improving further.
Last edited by Little Mouse; 02-28-2015 at 09:50 AM.
02-28-2015, 11:54 AM
#31
Race Director
I agree w/ the cheap guys. The point of my post wasn't to say what to do, but what is possible as some people earlier in the thread were saying that it's impossible to build HP in CA. I built a 450/480 engine AND passed smog - easily.
The recurve is so cheap and easy its power / $$ value is almost infinite.
After that, exhaust is a huge improvement on these cars. Some people have argued with me over the value of headers, but adding long-tube headers dropped nearly 3/4 second on my 0-60 time with an L-48 (7.1 - 6.5 sec). You could feel this power immediately - the car felt better everywhere. Upgrading to dual 2.5" exhaust helped quite a bit as well, taking the time to 6.2 sec. That change I couldn't really feel as much.
I did heads&cam after that which took the 0-60 to 5.6 sec.
I've since done this engine, which added a much needed static compression ratio boost (around or at least 2 pts, from 8.x (or less) to 10.2), newer AFR heads, a roller cam and an extra few CI. This was definitely a change I could feel.
The recurve is so cheap and easy its power / $$ value is almost infinite.
After that, exhaust is a huge improvement on these cars. Some people have argued with me over the value of headers, but adding long-tube headers dropped nearly 3/4 second on my 0-60 time with an L-48 (7.1 - 6.5 sec). You could feel this power immediately - the car felt better everywhere. Upgrading to dual 2.5" exhaust helped quite a bit as well, taking the time to 6.2 sec. That change I couldn't really feel as much.
I did heads&cam after that which took the 0-60 to 5.6 sec.
I've since done this engine, which added a much needed static compression ratio boost (around or at least 2 pts, from 8.x (or less) to 10.2), newer AFR heads, a roller cam and an extra few CI. This was definitely a change I could feel.
03-01-2015, 06:56 AM
#32
Recurve your distributor and spend money improving your very bad exhaust system. Your L/48 cam is a very low lift 4500 rpm cam. Don't need to spend money on a different intake to supply air to this rpm level. If your going to change cam and heads then consider a better intake manifold.
Aftermarket heads are slotted for extra push rod clearance needed to use 1.6 rockers. Your factory heads are not. 1.6 rockers will also put more strain on your lobes and lifters that are already old. Also your cam is 3.90/4.10 lift even adding a 1.6 is a very tiny help to this cam.
Spend money for a better stall converter if you have an auto not on 1.6 rockers.
Aftermarket heads are slotted for extra push rod clearance needed to use 1.6 rockers. Your factory heads are not. 1.6 rockers will also put more strain on your lobes and lifters that are already old. Also your cam is 3.90/4.10 lift even adding a 1.6 is a very tiny help to this cam.
Spend money for a better stall converter if you have an auto not on 1.6 rockers.
Thanks
03-01-2015, 01:31 PM
#33
Race Director
Generally speaking, the springs that come w/ a factory distributor have a very slow advance rate and you don't get full timing until way up in the RPM band.
Lighter springs will make the full mechanical advance come in quicker.
03-01-2015, 06:09 PM
#34
Pro
03-01-2015, 07:16 PM
#35
So get this
http://www.summitracing.com/int/part...model/corvette
?
Its only $30 than the internal tune up kit but seems to have 5 springs not 6
http://www.summitracing.com/int/part...model/corvette
As for the rear gears
https://www.rockauto.com/catalog/x,c...79%2BCHEVROLET
What do i buy for 3.36 since i highway drive and dont want high reeving ... even thou i have a Cali 1980 i dont think there is lock up, it sits at 2500rpm at 60mph
http://www.summitracing.com/int/part...model/corvette
?
Its only $30 than the internal tune up kit but seems to have 5 springs not 6
http://www.summitracing.com/int/part...model/corvette
As for the rear gears
https://www.rockauto.com/catalog/x,c...79%2BCHEVROLET
What do i buy for 3.36 since i highway drive and dont want high reeving ... even thou i have a Cali 1980 i dont think there is lock up, it sits at 2500rpm at 60mph
Last edited by R6n350GT; 03-01-2015 at 07:21 PM.
