Opinions wanted
I have a ’67 Belvedere with a tired old 318 in it. I would like something with a little more oomph. I don’t need a rocket ship, just enough power to merge into freeway traffic without having to turn the a/c off. I have access to a ’74 318 with only 25,000 miles on it. Compression and oil pressure are good; and it doesn’t smoke. How well would the motor respond to a mild cam, headers, and an intake and 4 barrel, being that it still a low compression motor with restrictive heads? Would it be worth the money spent for the upgrades? If so, can anyone recommend a particular cam?
ALSO, I am probably going to install this motor regardless if I make the upgrades or not since my current motor smokes and holds only about 15 psi of oil pressure at hot idle. My next question is how should I prep the engine block to put a fresh coat of paint on it. I just don’t want the new ’67 red paint to start flaking off to reveal the blue ’74 paint underneath.
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You can make the 318 run good...
The first thing that you need to do to increase the performance on a 318 is to put dual exhaust on it... 2 1/4" or 2 1/2" will work fine along with a good set of turbo mufflers of your choice that have low restriction... Installing dual exhaust on a 318 made the most performance increase of all the mods, and will complement later mods to the engine...
The second thing to do to increase the performance on a 318 is to go with a 4bbl...
Stay with the 74 318:
If you want to keep the 74 318 with minimal mods, I would first install a double roller timing chain, the stock 318 timing chains are junk...
Here's a nice true roller double roller chain that I've run for decades and put well over 150,000 miles on them and they hold up great and don't stretch so much...
https://www.manciniracing.com/edelbrock4.html
I would recommend installing a cam while you already have it apart for the timing chain... This one would work great with a set of Rhoades variable duration lifters:
https://www.amazon.com/gp/product/B000CEO7E4?ref=em_1p_0_ti&ref_=pe_3731750_439481530
Here's the Rhoades lifters:
https://www.summitracing.com/search/part-type/lifters?SortBy=BestKeywordMatch&SortOrder=Ascending&keyword=rhoades lifters 2018
Here's some information on Rhoades lifters, they bleed down below 3500 RPM to tame out the cam and give more low end and mid range vacuum and torque/power and pump up over 3500 RPM without sacrificing top end performance of the cam... Here's the Rhoades lifter main page:
https://www.rhoadslifters.com/
Scroll down to the second article on the "smart lifter" here for a more detailed explaination on how they work:
https://www.rhoadslifters.com/Pages/Articles.html
I've run Rhoades lifters in all my engines for the last 30 years and have had great results... I've run engines over 200,000 with them and no issues...
Then install a Wiand Stealth dual plane intake, they have a power band of idle - 6800 RPM
https://www.summitracing.com/parts/wnd-8022wnd/overview/make/dodge
I like the Holley 80457 600 CFM vacuum secondary carb for street drivers, they are calibrated for a late 60's engine and come with electric choke which makes them great for street driving... Just hook up the choke to the positive input side of the ballast resistor with a piggyback flat blade terminal and adjust the choke and you can drive it in all types of weather... I've driven them on daily drivers in winter in the midwest with great results... When the electric choke is adjusted properly, just pump the gas twice and start the car, then when the oil pressure comes up, put it in gear and drive away with no bogs or stumbles... Even in 20° F and below or warm weather...
Here's the link for the 80457, it is cheaper than the standard 1850 600 vacuum secondary Holley which is a manual choke, the 80457 comes with the electric choke already...
https://www.manciniracing.com/homo41noflca.html
Then run this base gasket as it's thicker to help insulate the carb from heat and vapor lock, has the center divider to keep the vacuum signal strong all the way to the carb, and comes with the mounting studs and nuts...
https://www.manciniracing.com/hein4sqboe.html
To adapt the 74 318 to your 67 Belvidere:
To put the 74 year engine in the 67 car, transfer the front of the 67 engine to it... This means use the 67 timing chain cover, cast iron water pump, 67 timing tab, alternator mounting brackets, pulleys and belts... I would keep the original vibration damper that came with the 74 318, but the mark for TDC will be 90° off as they changed the timing marks on the timing chain cover for 1970 and later small blocks and moved the lower radiator hose outlet to the opposite side... If you install the timing chain cover from the 67 318 on the 74 and then run the cast iron water pump as the 67 318's had, then you will be able to run the stock radiator in your 67 Belvidere and also run the original 67 alternator mounting brackets and pulleys...
The only thing that you will need to do is use the bolt on timing tab from the 67 318 and put the "new" 318 at TDC, then make a mark on the 74 vibration damper to line up with the TDC mark on the 67 timing tab... Now you will be able to use all of the original alternator, pulleys, belts, radiator, and original molded radiator hoses and not have to use the cheapo flex hoses....
Use 318 heads:
If you want to use the parts that you have and optimize the setup, I would recommend taking the 67 318 heads and install them on the 74 318... If both heads are stock, you will need to have hardened seats installed on the exhaust valves... Without hardened seats I've ruined seats in less than 10,000 miles on unleaded gas... So if you are going to have hardened seats installed, I would recommend reconditioning the 67 heads as they have smaller combustion chambers and will bump up the compression of the 74 318 to about 8.0 or a little higher...
If you want the 318 heads to run with the 360 heads, have them mild ported and install 360 valves in them... 1.88" intakes and 1.60" exhaust valves when you get the valve job done... I've had my head guy do that for me on a set of 67 318 heads that I'm building on a 72 318... With the mild porting and the larger valves, they will be comparable to the 360 heads without sacrificing any compression...
If you want to install 360 heads:
If you put 360 heads on the 74 318, your compression will be down to 7.5... I did it on a 72 318... However the increased flow will benefit more than the compression drop....
If you want to put 360 heads on it and keep the compression up, go with a set of 10.5 compression pistons which will end up at 9.2 compression with the larger combustion chambers of the 360 heads...
Painting:
I use a wire wheel mounted to a drill to clean off the dirt and old paint... Whatever won't come off with the wire wheel is stuck on there good and will be fine under the new paint... Then spray the engine with some carb or brake cleaner and clean off any residual grease and oil so the primer and paint will stick well...
I like to use primer under the paint as that's what my brother recommended to me and he's done body work for over 12 years.... The primer helps the paint stick better...
I have found that the Mopar Performance engine spray paint is much thicker than the plasti-kote engine paint... When I helped my buddy Eddie build a 340 for his Dart, he used the Mopar Performance paint and I was impressed with how thick it went on and how well it stuck compared to the plasti-kote that I've been using for decades...
Here's a link for the MP engine paint, choose your color:
https://www.manciniracing.com/mope10.html
