Hi I am new to the forum.I recently bought a restored 68 ss camaro 4speed 350 car with 3.42 rear gears.The car will be driven to cruise nights mostly and some car shows but I want the car to run respectably. The car has double hump 2.02 , 1.6 valves with 64cc chambers, it also has a dual plane intake and edelbrock 600 cfm carb. I thought it might be nice to keep the heads to be somewhat period correct but I am not sure what kind of power I can produce with them. The engine I would like to keep around 10.1 with flat tops, and I will keep quench to .035 or .040. Would I be better off to buy like a edelbrock power package rpm 410hp/408tq or can I build something better all suggestions welcomed. Thank you Delwin
350 sbc build
- Thread starter 76 camaro
- Start date
philly
solid fixture here in the forum
first off, welcome to the site! and it sounds like you have a really nice hot rod on your hands! posting pics would certainly contribute to the blood flow around here.
as per your question, the 400lbft of torque goal can and has been reached with your double humps many times with your displacement. if you want to keep all of your numbers matching gear and make more power i would recommend looking into porting the stock heads ( as the cylinder head and its airflow capacity is usually the biggest bottleneck to unlocking real power potential) and then port matching the intake manifold to those heads so as to maximize all the effort you just put in. as always on grumpys performance, theres no shortage of reading materials and when taking on a port job it would be wise to read these links (and their sublinks) carefully, a couple times, to make sure you grasp the job your about to undertake before you start carving them heads up like a jack-o-lantern.
another couple ways to go quicker with your present combo, first, would be to swap out the ring and pinion gears, i understand the 4spd doesnt have an overdrive gear so its really your preference but 3.73 or 4.11 depending on your comfort level will certainly wake the car up.
heres some related info:
next would be to get yourself a larger (cfm) and more modern design of carburetor. (the shortcut formula to find a carburetor cfm size is roughly CIDxRPM divided by 3456) where rpm will your intended shift point (plus 500 rpm to account for overspeed) and that should get you a cfm number more commensurate with your intended use.
if the car doesnt have a well thought out exhaust with appropriately sized headers and low or no restriction piping then you can also make huge gains in that department.
and lastly once the whole combination is laid out the final piece to the puzzle would be the camshaft. theres plenty of info on this forum about different camshaft selection ideas... heres a couple to get you started.
i know that seems overwhelming but believe its better to learn everything you can about the stuff BEFORE YOU BUY PARTS than afterwards... ive only been on this site a year and its saved me alot of money and headaches being able to share ideas with these guys while they are still in the planning stages, instead of coming here looking for internet diagnosis to problems i could have avoided. thumbs up and please post some pics of the camaro i love me some muscle cars.
SAFE piston speeds are best restricted to 4000fpm for stock components and 4500fpm for the better common aftermarket components
if your serious about building a performance engine you might want to consider a BBC over a SBC
you can generally expect to get between 1.0 to 1.3 ft lbs per cubic inch of displacement and 1.0 to 1.3 horsepower per cubic inch of displacement on your average street/strip daily driver SBC or BBC engine build
how the big block and small block engines differ. The answer is not only in displacement. A small block Chevy motor can be stroked and bored to over 400 ci . it comes down to bore centers. and much stronger OEM blocks and generally better flowing heads, The small block has bore centers spaced 4.4 inches apart. On the big block, those centers are at 4.84 inches.
as a general rule you can build a 396-402 BBC that can outperform a 400 SBC, you'll have a difficult time finding SBC heads that flow more than 310 cfm at a decent price, but many BBC heads flow in excess of 350 cfm, especially if mildly ported and aftermarket BBC heads that flow over 400 cfm are available
keep in mind your basic BBC With more metal separating the bores, there's extra space for cooling galleries and added potential for boring-out. Further, more metal means a stronger block. cranks and rods and the basic BBC block are significantly stronger than the average OEM sbc parts, If you're looking for big horsepower from your muscle car motor, a big block might be the way to go.
read these threads
as per your question, the 400lbft of torque goal can and has been reached with your double humps many times with your displacement. if you want to keep all of your numbers matching gear and make more power i would recommend looking into porting the stock heads ( as the cylinder head and its airflow capacity is usually the biggest bottleneck to unlocking real power potential) and then port matching the intake manifold to those heads so as to maximize all the effort you just put in. as always on grumpys performance, theres no shortage of reading materials and when taking on a port job it would be wise to read these links (and their sublinks) carefully, a couple times, to make sure you grasp the job your about to undertake before you start carving them heads up like a jack-o-lantern.
another couple ways to go quicker with your present combo, first, would be to swap out the ring and pinion gears, i understand the 4spd doesnt have an overdrive gear so its really your preference but 3.73 or 4.11 depending on your comfort level will certainly wake the car up.
heres some related info:
next would be to get yourself a larger (cfm) and more modern design of carburetor. (the shortcut formula to find a carburetor cfm size is roughly CIDxRPM divided by 3456) where rpm will your intended shift point (plus 500 rpm to account for overspeed) and that should get you a cfm number more commensurate with your intended use.
if the car doesnt have a well thought out exhaust with appropriately sized headers and low or no restriction piping then you can also make huge gains in that department.
and lastly once the whole combination is laid out the final piece to the puzzle would be the camshaft. theres plenty of info on this forum about different camshaft selection ideas... heres a couple to get you started.
i know that seems overwhelming but believe its better to learn everything you can about the stuff BEFORE YOU BUY PARTS than afterwards... ive only been on this site a year and its saved me alot of money and headaches being able to share ideas with these guys while they are still in the planning stages, instead of coming here looking for internet diagnosis to problems i could have avoided. thumbs up and please post some pics of the camaro i love me some muscle cars.
SAFE piston speeds are best restricted to 4000fpm for stock components and 4500fpm for the better common aftermarket components
if your serious about building a performance engine you might want to consider a BBC over a SBC
you can generally expect to get between 1.0 to 1.3 ft lbs per cubic inch of displacement and 1.0 to 1.3 horsepower per cubic inch of displacement on your average street/strip daily driver SBC or BBC engine build
how the big block and small block engines differ. The answer is not only in displacement. A small block Chevy motor can be stroked and bored to over 400 ci . it comes down to bore centers. and much stronger OEM blocks and generally better flowing heads, The small block has bore centers spaced 4.4 inches apart. On the big block, those centers are at 4.84 inches.
as a general rule you can build a 396-402 BBC that can outperform a 400 SBC, you'll have a difficult time finding SBC heads that flow more than 310 cfm at a decent price, but many BBC heads flow in excess of 350 cfm, especially if mildly ported and aftermarket BBC heads that flow over 400 cfm are available
keep in mind your basic BBC With more metal separating the bores, there's extra space for cooling galleries and added potential for boring-out. Further, more metal means a stronger block. cranks and rods and the basic BBC block are significantly stronger than the average OEM sbc parts, If you're looking for big horsepower from your muscle car motor, a big block might be the way to go.
read these threads
Last edited by a moderator:
philly
solid fixture here in the forum
also with the camshaft selection, realize you are working with stock heads that have mediocre exhaust ports in relation to their intakes, so a longer duration on the exhaust lobe would be more beneficial than a straight up cam... depending on your other choices for parts, this seems like a good deal to freshen up everything cam and valve related:
http://www.lunatipower.com/Product.aspx?id=8669&gid=401
its definitely got the LSA, overlap and lift for what you want to do, however that same profile with more and more lift will probably keep gaining power up to like .600" lift all else being the same, i just dont know if theres a cam company thatll build you a cam with ramp rates like that on an inexpensive flat tappet cam you may be able to squeeze off a few extra ponies bumping up to 1.6 or 1.7 rockers.... yea theres threads here on that too... its definitely not as easy as it sounds....
viewtopic.php?f=52&t=10671&p=46039&hilit=rocker+arm+ratio#p46039
http://www.lunatipower.com/Product.aspx?id=8669&gid=401
its definitely got the LSA, overlap and lift for what you want to do, however that same profile with more and more lift will probably keep gaining power up to like .600" lift all else being the same, i just dont know if theres a cam company thatll build you a cam with ramp rates like that on an inexpensive flat tappet cam you may be able to squeeze off a few extra ponies bumping up to 1.6 or 1.7 rockers.... yea theres threads here on that too... its definitely not as easy as it sounds....
viewtopic.php?f=52&t=10671&p=46039&hilit=rocker+arm+ratio#p46039
8
87vette81big
Guest
A Big Block Chevy is a natural swap into a 1st gen Camaro.
396, 402, 427 , 454.
Grumpy likes the 496 BBC based off a truck tall deck 427.
Your original Double hump 2.02 heads are worth $$$ to the right person restoring.
I wouldn't port.
Sell them or save them .
Stock original hard to find today.
396, 402, 427 , 454.
Grumpy likes the 496 BBC based off a truck tall deck 427.
Your original Double hump 2.02 heads are worth $$$ to the right person restoring.
I wouldn't port.
Sell them or save them .
Stock original hard to find today.
76 camaro said:
Welcome to the website, glad you found us!!!
Hope you don't mind, I changed the resolution on your picture. It was so big, I
could only see about 1/2 the car. That is such a beautiful car, it's definitely
worth seeing all of it.
This thread will help with posting pictures here and the software is free. You
might want to page down to the "Software" section for the resizing of photos,
the first part is about taking the photos.
viewtopic.php?f=25&t=5595
You didn't mention your budget, it always come down to the budget when
building cars. How much are you looking to spend? They say ..... speed cost
money, how fast do you want to go. But also RPM cost money, have you gotten
an idea about how hard you want to twist this motor? Keeping the mean piston
speed below 4000 Feet Per Minute (FPM), is generally a safe speed for a street
motor. Check out this thread for a table to help you with this.
viewtopic.php?f=99&t=3370
Strictly Attitude
solid fixture here in the forum
Very nice car!! It has all been stated already got make some key decisions. Purist or hot rod first one. Build or buy another big one. Budget come up with a good honest number.