Ready to give in,
Thread Starter
Melting Slicks
Joined: Mar 2006
Posts: 3,342
Likes: 7
From: Connecticut
Ready to give in,
Ok, Stock 73' L-48 and after driving my 70 El Camino SS 454 today for the first time in almost two years I think Its time to update the L-48 (which needs valve guide seals by the way)
I have been against installing headers since my first Corvette... (also a 73') because of hot foot and starter issues. I sold the car in 1984 to buy a brand new Z/28.
My first 73' was far from stock and really had some ******.
Anyhow, I have been thinking about a top end package to gain some more HP and torque but I really dont want to get involved with replacing the cam shaft due to the radiatior removal but I have decided on Hooker headers and Side Exhaust
Question is what would I possibly gain by changing to a smaller cc chamber head and the Hooker setup without changing the cam shaft?
Is it worth the bother, if so what could I expect for a ballpark increase in power and what brand/model/size heads would be best for my application if any?
Thanks
Bob
I have been against installing headers since my first Corvette... (also a 73') because of hot foot and starter issues. I sold the car in 1984 to buy a brand new Z/28.
My first 73' was far from stock and really had some ******.
Anyhow, I have been thinking about a top end package to gain some more HP and torque but I really dont want to get involved with replacing the cam shaft due to the radiatior removal but I have decided on Hooker headers and Side Exhaust
Question is what would I possibly gain by changing to a smaller cc chamber head and the Hooker setup without changing the cam shaft?
Is it worth the bother, if so what could I expect for a ballpark increase in power and what brand/model/size heads would be best for my application if any?
Thanks
Bob
Drifting
Joined: Mar 2005
Posts: 1,806
Likes: 3
From: Burlington WI
My .02
If you plan on replacing the heads you should also put a decent cam in to compliment them. The L48 cam isnt much for performance.
Just the vortec style heads alone are supposed to add 30 - 40 HP.
Headers and duals only help the situation.
How many miles are on the engine??
If you throw a set of fresh heads on there without any other considerations you may very well open up another can of worms and discover that "WHILE I'M AT IT" you should have looked at the rings and bearings as well.
Chris B
Just the vortec style heads alone are supposed to add 30 - 40 HP.
Headers and duals only help the situation.
How many miles are on the engine??
If you throw a set of fresh heads on there without any other considerations you may very well open up another can of worms and discover that "WHILE I'M AT IT" you should have looked at the rings and bearings as well.
Chris B
Safety Car
Joined: May 2005
Posts: 4,176
Likes: 7
From: Jennings LA
Originally Posted by fl_rider
If you plan on replacing the heads you should also put a decent cam in to compliment them. The L48 cam isnt much for performance.
Just the vortec style heads alone are supposed to add 30 - 40 HP.
Headers and duals only help the situation.
How many miles are on the engine??
If you throw a set of fresh heads on there without any other considerations you may very well open up another can of worms and discover that "WHILE I'M AT IT" you should have looked at the rings and bearings as well.
Chris B
Just the vortec style heads alone are supposed to add 30 - 40 HP.
Headers and duals only help the situation.
How many miles are on the engine??
If you throw a set of fresh heads on there without any other considerations you may very well open up another can of worms and discover that "WHILE I'M AT IT" you should have looked at the rings and bearings as well.
Chris B
and pulling the radiiator to change the cam might take an hour at most. do it 
Pro
Joined: Nov 2004
Posts: 575
Likes: 0
From: Nice Lake Ontario
I double
Those L-48 cams really suck!
I ran a solid LT-1 in my 74 but any good cam will really help perk up that engine especially with other mods you have planned
Pulling the rad is no big deal anyway!
Those L-48 cams really suck!
I ran a solid LT-1 in my 74 but any good cam will really help perk up that engine especially with other mods you have planned
Pulling the rad is no big deal anyway!
Thread Starter
Melting Slicks
Joined: Mar 2006
Posts: 3,342
Likes: 7
From: Connecticut
The engine has about 6 or 7 thousand miles on a full rebuild but it sat for 11 years (thats why the valve guide seals leak)
I have never removed a C3 radiator but thought it was a nightmare to remove...shroud ect.
I have never removed a C3 radiator but thought it was a nightmare to remove...shroud ect.
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Thread Starter
Melting Slicks
Joined: Mar 2006
Posts: 3,342
Likes: 7
From: Connecticut
Originally Posted by dgruenke
Definitely going to want to replace the cam. It only takes a day to get it done by itself, but if you have most of the stuff off anyway, it won't take very long to pull the radiator.
Will I need new pushrods, flat tappett or rollers ect:
Thanks
Drifting
Joined: Apr 2002
Posts: 1,716
Likes: 4
From: New Baden Illinois
The options for the heads and cam are virtually limitless. It all depends on what you want out of the car and how much you are willing to spend to get there.
If you just want a decent street motor that has some punch, you can probably go with some World Product or Dart iron heads that will give you a great deal more flow than the stock heads. For the cam, it somewhat depends on whether you have an automatic or manual. If you have an automatic, you can only go so big without getting a different torque converter.
Another option is to buy one of the top end kits that is already matched, but most of those come with the intake also.
If you just want a decent street motor that has some punch, you can probably go with some World Product or Dart iron heads that will give you a great deal more flow than the stock heads. For the cam, it somewhat depends on whether you have an automatic or manual. If you have an automatic, you can only go so big without getting a different torque converter.
Another option is to buy one of the top end kits that is already matched, but most of those come with the intake also.
Race Director
Joined: Aug 2004
Posts: 10,628
Likes: 132
From: Duvall, WA
I've never done it on a '73, but removing the radiator on my '71 is a piece of cake. I think it takes longer for the coolant to drain out than it does to get the radiator out once it is empty.
Thread Starter
Melting Slicks
Joined: Mar 2006
Posts: 3,342
Likes: 7
From: Connecticut
Originally Posted by rcread
I've never done it on a '73, but removing the radiator on my '71 is a piece of cake. I think it takes longer for the coolant to drain out than it does to get the radiator out once it is empty.
I have read so many horror stories of removing the shroud,,, cutting them in 1/2 with a sawzall ect: to get the radiator out
I would like to see close to 300 HP with the stock pistons for less than $2,000
I would prefer heads that were completely assembled that only require the valves to be adjusted
Keep in mind this is a 2 bolt main block
Thanks for all your help
Le Mans Master
Joined: Sep 2001
Posts: 7,739
Likes: 630
From: Unreconstructed, South Carolina
Originally Posted by Bob Onit
Ok, Stock 73' L-48 ... Its time to update the L-48 (which needs valve guide seals by the way)
The engine has about 6 or 7 thousand miles on a full rebuild but it sat for 11 years (thats why the valve guide seals leak)
I already have an Edelbrock performer intake
Keep in mind this is a 2 bolt main block
I would like to see close to 300 HP with the stock pistons for less than $2,000
Thanks
Bob
The engine has about 6 or 7 thousand miles on a full rebuild but it sat for 11 years (thats why the valve guide seals leak)
I already have an Edelbrock performer intake
Keep in mind this is a 2 bolt main block
I would like to see close to 300 HP with the stock pistons for less than $2,000
Thanks
Bob
You're asking for about 300HP ...rear wheel hp? ... or flywheel hp?
If 300 at crank (fwhp) you're not asking for much ... this'll be easy & not cost much ... but it will involve a cam.
All 73 L48 had dished pistons when new ... when it was rebuilt, were dished installed or flattops? Were heads milled? Are head gaskets thin steel shim or thicker composition?
All 73 came OE w/ a pretty good true dual exhaust ... headers won't add much to a relatively low HP application.
Race Director
Joined: Dec 2000
Posts: 10,896
Likes: 2
From: CO
You could just enjoy a car that runs. I know, that IS crazy talk. But really its going to take a lot of time / money to upgrade. If you enjoy it and have the money do it. Otherwise just enjoy the car itself.
Thread Starter
Melting Slicks
Joined: Mar 2006
Posts: 3,342
Likes: 7
From: Connecticut
Originally Posted by jackson
Bob:
You're asking for about 300HP ...rear wheel hp? ... or flywheel hp?
If 300 at crank (fwhp) you're not asking for much ... this'll be easy & not cost much ... but it will involve a cam.
All 73 L48 had dished pistons when new ... when it was rebuilt, were dished installed or flattops? Were heads milled? Are head gaskets thin steel shim or thicker composition?
All 73 came OE w/ a pretty good true dual exhaust ... headers won't add much to a relatively low HP application.
You're asking for about 300HP ...rear wheel hp? ... or flywheel hp?
If 300 at crank (fwhp) you're not asking for much ... this'll be easy & not cost much ... but it will involve a cam.
All 73 L48 had dished pistons when new ... when it was rebuilt, were dished installed or flattops? Were heads milled? Are head gaskets thin steel shim or thicker composition?
All 73 came OE w/ a pretty good true dual exhaust ... headers won't add much to a relatively low HP application.
I am the fourth owner
The original owner was a woman who is now in her 70's
She owned it for 20 years, she had the engine rebuilt and shortly after that it she sold it.
The next owner had it for 11 years and put a total of 2,000 miles on it.
He then sold it to the third owner...the person I bought it from, The person I bought it from did not know which end of a screwdriver to hold and (from what I gathered) was afraid to drive it as he had to pay big $$$ for even the smallest repairs ( I have a folder about 3 inches thick of repairs paid for from the person I bought it from)
He now owns a 2003, I saw the car when I went to look at mine.
He put less than 300 miles on the car in the year that he owned it and dumped a ton of money in to it.
I did speak to the company that did the rebuild but his computer records only go back to 1996.. But... He did remember the woman and the car and did verify a full rebuild...I have no idea what pistons are installed, I would Imagine the stock pistons are still in place but I cant be sure
Long interesting saga
As far as flywheel or brake HP I dont know
At this time it is rated at 190HP so 300 would be a definate improvement.
Le Mans Master
Joined: Aug 2000
Posts: 6,273
Likes: 14
From: Austin TX
I ran a set of Trick Flows with an Edelbrock performer 2101 and a Crane 272 with an average bottom end for a few years and was very happy with it.
You might check with Edelbrock on packages that include heads, cam and intake that are matched.
You probably will need a new carb or TBI to finish off the top end.
You will need a better exhaust to take advantage of this. Use 2.5" pipes, an x crossover and hi flow muffs like magnaflo, Flowmaster, Walker turbos or Edelbrock RPMs. Headers will also help.
You might check with Edelbrock on packages that include heads, cam and intake that are matched.
You probably will need a new carb or TBI to finish off the top end.
You will need a better exhaust to take advantage of this. Use 2.5" pipes, an x crossover and hi flow muffs like magnaflo, Flowmaster, Walker turbos or Edelbrock RPMs. Headers will also help.
Le Mans Master
Joined: Sep 2001
Posts: 7,739
Likes: 630
From: Unreconstructed, South Carolina
Bob:
In short, you can't answer for what's in the motor ... OK ... no way for you to know.
There's confusion regarding HP rating ... the WAY the HP was determined changed throughout 70's and that has major effect on WHAT the HP results are. Someone else can chime in w/ those details but what follows may help show what's practical:
All STOCK L48 are equal internally ... take any STOCK L48 in good shape & in good tune to any reputable shop with an engine dyno and everyone of em will make between 250-280HP (flywheel or crank HP). The motor is pulling against only the dyno and the motor's water pump ... no other accessories. That's same way all motors are rated when you see ads for crate motors or heads, cams etc that claim certain HP or HP increase. If your "190HP" motor in good shape & good tune it'll make 250-280.
Take your heads & have em straightened & serviced ... along w/ a fresh $25 set of Z28 springs ... total probably under $250. Install heads w/ thin steel shim gaskets FelPro P/N 1094 ... under $50/pr. I seldom recommend summit because most of their stuff is too high priced ... but their brand cam kits are exception. Install a mild Summit cam & lifter kit P/N SUM-K1103 ... about $70 (.442"/.465" 212*/224*). Use a new timing chain set like Cloyes P/N 9-3023X ... under $25. New set of pushrods about $25 ... new stamped rockers about $35. Then your motor will make about 310HP-325HP at crank ... reliably & w/ good manners ... cost out @ about $500 and 2 weekends ... no BS. Your other threads indicate you have a pretty good handle on Qjet & distributor tuning. G'Luck!
In short, you can't answer for what's in the motor ... OK ... no way for you to know.
There's confusion regarding HP rating ... the WAY the HP was determined changed throughout 70's and that has major effect on WHAT the HP results are. Someone else can chime in w/ those details but what follows may help show what's practical:
All STOCK L48 are equal internally ... take any STOCK L48 in good shape & in good tune to any reputable shop with an engine dyno and everyone of em will make between 250-280HP (flywheel or crank HP). The motor is pulling against only the dyno and the motor's water pump ... no other accessories. That's same way all motors are rated when you see ads for crate motors or heads, cams etc that claim certain HP or HP increase. If your "190HP" motor in good shape & good tune it'll make 250-280.
Take your heads & have em straightened & serviced ... along w/ a fresh $25 set of Z28 springs ... total probably under $250. Install heads w/ thin steel shim gaskets FelPro P/N 1094 ... under $50/pr. I seldom recommend summit because most of their stuff is too high priced ... but their brand cam kits are exception. Install a mild Summit cam & lifter kit P/N SUM-K1103 ... about $70 (.442"/.465" 212*/224*). Use a new timing chain set like Cloyes P/N 9-3023X ... under $25. New set of pushrods about $25 ... new stamped rockers about $35. Then your motor will make about 310HP-325HP at crank ... reliably & w/ good manners ... cost out @ about $500 and 2 weekends ... no BS. Your other threads indicate you have a pretty good handle on Qjet & distributor tuning. G'Luck!
Thread Starter
Melting Slicks
Joined: Mar 2006
Posts: 3,342
Likes: 7
From: Connecticut
Originally Posted by jackson
Bob:
In short, you can't answer for what's in the motor ... OK ... no way for you to know.
There's confusion regarding HP rating ... the WAY the HP was determined changed throughout 70's and that has major effect on WHAT the HP results are. Someone else can chime in w/ those details but what follows may help show what's practical:
All STOCK L48 are equal internally ... take any STOCK L48 in good shape & in good tune to any reputable shop with an engine dyno and everyone of em will make between 250-280HP (flywheel or crank HP). The motor is pulling against only the dyno and the motor's water pump ... no other accessories. That's same way all motors are rated when you see ads for crate motors or heads, cams etc that claim certain HP or HP increase. If your "190HP" motor in good shape & good tune it'll make 250-280.
Take your heads & have em straightened & serviced ... along w/ a fresh $25 set of Z28 springs ... total probably under $250. Install heads w/ thin steel shim gaskets FelPro P/N 1094 ... under $50/pr. I seldom recommend summit because most of their stuff is too high priced ... but their brand cam kits are exception. Install a mild Summit cam & lifter kit P/N SUM-K1103 ... about $70 (.442"/.465" 212*/224*). Use a new timing chain set like Cloyes P/N 9-3023X ... under $25. New set of pushrods about $25 ... new stamped rockers about $35. Then your motor will make about 310HP-325HP at crank ... reliably & w/ good manners ... cost out @ about $500 and 2 weekends ... no BS. Your other threads indicate you have a pretty good handle on Qjet & distributor tuning. G'Luck!
In short, you can't answer for what's in the motor ... OK ... no way for you to know.
There's confusion regarding HP rating ... the WAY the HP was determined changed throughout 70's and that has major effect on WHAT the HP results are. Someone else can chime in w/ those details but what follows may help show what's practical:
All STOCK L48 are equal internally ... take any STOCK L48 in good shape & in good tune to any reputable shop with an engine dyno and everyone of em will make between 250-280HP (flywheel or crank HP). The motor is pulling against only the dyno and the motor's water pump ... no other accessories. That's same way all motors are rated when you see ads for crate motors or heads, cams etc that claim certain HP or HP increase. If your "190HP" motor in good shape & good tune it'll make 250-280.
Take your heads & have em straightened & serviced ... along w/ a fresh $25 set of Z28 springs ... total probably under $250. Install heads w/ thin steel shim gaskets FelPro P/N 1094 ... under $50/pr. I seldom recommend summit because most of their stuff is too high priced ... but their brand cam kits are exception. Install a mild Summit cam & lifter kit P/N SUM-K1103 ... about $70 (.442"/.465" 212*/224*). Use a new timing chain set like Cloyes P/N 9-3023X ... under $25. New set of pushrods about $25 ... new stamped rockers about $35. Then your motor will make about 310HP-325HP at crank ... reliably & w/ good manners ... cost out @ about $500 and 2 weekends ... no BS. Your other threads indicate you have a pretty good handle on Qjet & distributor tuning. G'Luck!
Thank you VERY much!
Bob
Drifting
Joined: Apr 2002
Posts: 1,716
Likes: 4
From: New Baden Illinois
I am not sure if that will get you there with the stock heads. I put the Crane 266H (.440/.440) in mine a few years ago with true duals undercar chambered exhaust and only came up with about 180 rwhp and about 250 ft.lbs. of torque. Everything else being stock except for the air cleaner (K&N).