hello everyone
im thinking about doing a few mods to my stock l48 in my 77. plans call for sidepipes , headers and if possible i would like to run a dual quad intake. possibly a tunnel ram with small( 390-450 cfm) carbs. id like to have a nice lopey idle too. i admit while i do my own work i dont have a lot of internal engine experience. if it is possible id like to stay away from having to get a new stall converter. looking for something remotely steetable as this car will never see a dragstrip and will rarely ever be driven hard. everyone says to stay away from the dual quad set up but i really like the visual impact it gives when you raise the hood. the intake plans are not etched in stone . what im really looking for is the sound and lope of an old school 3/4 cam. but im ignorant of what to look for as far as lift , duration , etc about camshafts. as i said id like to run the 2 fours and will need a capable camshaft. i am doing to port the intake to the heads but thats all the headwork i really weant to do.
im not a speed demon but dont want to be a poser either.
please help
billy

 

as a guy who spent $$$$$$$$$ to get this set up to work on a BBC, let me ask some questions first.

1- are you really sure you want to cut a hole in the hood?

2- if its not set up right, you will wash a cylinder on the street and eat the motor, are you ready to spend $$

3- T-Ram is a high mid RPM to high rpm intake better make sure the motor is solid and balanced for that kind of RPM, good rods etc

4- There will not be much in the form of bottom end unless you have big compression or big displacement--keep this in mind its go big or go home


Not trying to be negative just being frank and real

 

You sound like a good candidate for a comp cams thumper series cam if all your looking for is a good sound and the car won't be raced or driven hard.

 

Here's my roller cam swap thread:http://forums.corvetteforum.com/c3-t...-cam-swap.html
With stock heads & compression your limited in your cam selection.You can build a nice performing L48 with new heads,cam,intake & exhaust. Good Luck!

 

as i said the tunnel ram is not etched in stone but i thought it would possible if i were to run the smaller carbs. i know nothing of carbs or cams but i figured running two 390 or less cfm would be similiar to running a 750 or 800 cfm carb. am i wrong ?

 

thank you

 

Have you considered running small wieand street supercharger?This will accomplish your
goals with mild cam and provide excellent street manners.You can run the supercharger on a stock engine up to 6psi if it is in good condition.As far as hood clearance goes I would ask others with same set up what is needed.

 

Your sending some mixed signals kind of. Side pipes are indentified with road racing and tunnel rams with drag racing sort of an odd couple together. Even street tunnel rams are in the 3,500 rpm up range, if you do one use bigger carbs then 390/450. Even edelbrocks dual planes want you to use 500cfm. It is what it is putting punny carbs on higher rpm manifolds does not bandaid anything only makes it into a non use thing, now only what you said a poser.

 

I see street cars with two-4s on them all the time, if you want them put them on.
The Comp Cams Thumper cam would be a great choice.

 

A small thumper cam will work with the low compression 77 350 .

 

I have the mild Thumper series cam for sale if your looking. I bought it before I realized all the performance trade offs for a cool sound like terrible fuel economy and less efficient power output. I went with a comp 268h because it came with the craigslist 355 I picked up to build but might change my mind again.....

If you want this to be fun to drive on the street and have quick stop sign acceleration than stick with something with a power and that starts around 1500 rpm..... otherwise it wont perform as well on the street and may even be less fun than stock without changing the converter and rear gears...

 

If you want that then drive grandma's Pontiac Bonneville.

If he wants to run 2 4s I think the gas mileage is the furthest from his mind and a lopey cam is the least of the challenges!

 

I would ditch the t-ram idea. Impractical unless you intend to show this car more than drive it.

Tune your engine around a nice Comp 268H or that thumpr cam. Rebuild/re-jet the (qjet?) carb, lay down a nice recurve on your distributor, headers and maybe even the sidepipes for effect... or a cool 1 5/8" full length headers and true duals setup with a loud pair of turbo mufflers instead of the sidepipes.

Refresh or replace your cylinder heads with a fresh, good flowing, 180-195cc pair.

Then, you can have lots of stoplight fun and you won't have a fortune in the setup.

That's what I'd do. Wait, that's what I did (but with Crane Energizer 272H10 grind)!

Since then, I've updated to a retro-roller setup. Hoping to finish it before summer driving season.

 

Ditto...that's what I did.... found everything to build a high nickel 4 bolt 355 with flat tops and dart iron eagle heads for about a grand on Craigslist..... Craigslist is great! Just research what your buying before talking to the seller...
Keep in mind you will get a lot of grief from others about the thumpr being a "poser" cam. They actually detune things causing the motor to waste a LOT of unburnt fuel and waste power .... all for the idle sound... I researched the cams a lot when I bought mine.... everyone says the same thing but the guys selling them.
One guy went from 9mpg to almost 13 when going to a bigger but better cam. And I'm not buying the whole gas mileage means nothing argument thing.... the fact is if it really didn't matter most of us likely wouldn't be driving c3's.... I love the car don't get me wrong.... just saying if the majority of us wanted to just throw extra money away each week we would likely have payments on newer toys to waste it on..

 

Mileage don't matter to me. If it dId I'd drive a prius or hybrid. Not a 6.2l sierra or my vette which gets around 8.5 mpg. The thumper cam has a mean sound and despite all some bite. You could still get some sound and serious bite with drivability out of a good cam. Go roller and you could go larger, getting more power, sound with the same manners. If you want that sound with out drivability then just pull a plug wire and call it a day.

 

Some people don't want a stock vette or the sound either.
You see 67 Novas and 69 Camaros running around with nasty sounding cams and I see no reason why a vette can't sound like that either they have the same engine!
Little Edelbrock Performer or Comp Cams 268 just isn't a rough sounding cam.
You want a mean sounding cam pick one with close to 300 duration and a 110/108 lobe separation.

 

You could consider running dual fours but on a low rise 2x4 intake like an Edelbrock and probably they would fit under your hood. If you want a rump-rump cam look at the old Crane energizer 274h06 218-218 .450 lift on a 106 LSA. It will idle with the lope your are looking for but still give you good low end. Thumper cam on a stock low compression engine like yours will be a real dog unless you have gears and a converter. You will have to do some tuning to get the dual fours to run properly but they will work. I have dual fours on a 455 Pontiac and they idle like a stock 4 barrel but took me some time to get all the jetting and metering rod specs dialed in.

 

No, thanks. I'm currently installing a Howard's retro HR .560" I/E into my 355.

 

Thats what I told myself when I bought a lifted ram with a 5.9 and 4.56 gears and 35"mudders...... 5 years later and I put about 6,000 miles on it....instead driving the company toyota or one of my other vehicles like my vw kit car...
Bottom line no matter how much you try to convince yourself otherwise the gas mileage DOES come into play when it comes to how much you do or dont drive the thing unless your loaded.... I'm not saying its a deal breaker but when you have the choice of a better running more powerful car with good vacuum and brakes or a cool sounding car that "fakes" the sound of a much bigger race cam at the cost of power driveability, braking power and gas mileage well.... Just google it and read up on all the people on other forums who used them and recommend against them because of issues or removed them for a better cam....they are a bitch to tune as well from what I've been told.
If you want to be the guy at the carshow with all the people who know nothing about cars loving it and all the people that do giving you the same look I get when riding by harley guys on my metric cruiser or taking my kitcar to a carshow then do it... but just keep it in mind that most "gear heads" think of the thumpr cams as the epitome of a fake "poser" Part. Obviously having the other toys I have and a lifted truck with "compensating" across the windshield I dont really care what others think and I like the sound of the thumpr cam myself and if it hadnt been for the other performance compromises I would have used it in my vette but I just cant justify it on sound itself.... its like the reverse flow mufflers in the sidepipes bolted to a built up engine choking the output out...

 

1: If a person can't afford a hotrod then they made a mistake buying or building one in the first place.
2:Just because a car has a loud exhaust and a lopey can doesn't mean its junk and has to be worked on all the time.
3: If I can't have what I want then I would rather do without instead of settling for something less.
4: I build an engine around the cam.