Thread: Advice on engine build

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Ok, so after everyone has told me I won't make any power from a 267, I've decided I'm going to get a 350. It's all stock from a 1978 chevy van. Plans are to get a 4 barrel intake, 4 barrel Holley 600cfm carb, headers, either noisy gear drive or double roller timing chain, comp valve springs, performer distributor, possibly port and polish the heads, and a cam. Now where I need advice is with the cam. I want something with a aggressive lopey sound, and also good power through the power band. I've found these 3 that I like on summit, Lunati bracket master II 292/292 duration and 480/480 lift, Lunati bracket master II 300/300 duration and 415/415 lift, and Summit Racing 303/313 duration and 487/508 lift. All 3 are hydraulic flat tappet cams. Oh and btw this engine will be backed by a turbo 350 with a shift kit. Any advice on these cams or any other cams is appreciated. Thanks!

Unless the rest of the car can support that Summit cam I would forget about it...
"Lopey idle, mid-upper rpm power. Works best with 10:1-11:1 compression, 3,000+ stall, and gearing. Works well with N2O and roots blower. "
A stock 78 350 is not going to have the compression ratio to make this cam work as it is designed. And, if you are still running the stock converter and 2.40 or 2.73 rear gears, this car will be a slug.
I know this isn't what you want to hear but, with a stock compression late 70's 350 you really need to keep the cam mild. I would design the engine to make maximum torque off idle up to about 4500 RPM. The car is big and heavy and you need that low-end oomph to get it moving. A mid-range lumpity-lump cam is not going to do that and you will not be happy with the performance.
Just my thoughts.
Mark

Your wasting a lot of money on STUFF that won't give you the performance your looking for and most likely will take away from the range you will be driving around in ----I'd really suggest you find a late model LIFT OUT engine package and convert that car to newer modern performance /economy------you can get complete liftouts reasonably priced from salvage yards and they include wiring, ecm, accessory and accessory drive packages plus exhaust manifolds that fit, won't leak, etc--------look for a 6.0 from late suv/pickup or Camaro

Stay under a .5 lift or you're asking for trouble.

You'll learn to hate noisy gears, ghe novelty will wear thin quickly.

Timing chains absorb harmonics that affect your ignition.

Originally Posted by 84Monte

Ok, so after everyone has told me I won't make any power from a 267, I've decided I'm going to get a 350. It's all stock from a 1978 chevy van. Plans are to get a 4 barrel intake, 4 barrel Holley 600cfm carb, headers, either noisy gear drive or double roller timing chain, comp valve springs, performer distributor, possibly port and polish the heads, and a cam. Now where I need advice is with the cam. I want something with a aggressive lopey sound, and also good power through the power band. I've found these 3 that I like on summit, Lunati bracket master II 292/292 duration and 480/480 lift, Lunati bracket master II 300/300 duration and 415/415 lift, and Summit Racing 303/313 duration and 487/508 lift. All 3 are hydraulic flat tappet cams. Oh and btw this engine will be backed by a turbo 350 with a shift kit. Any advice on these cams or any other cams is appreciated. Thanks!

Ditto what the other pros have said regarding big cams on the street. All 3 of those bumpsticks will kill vacuum, idle poorly and without the required thousands of $$$ worth of complementary engine and drivetrain upgrades, make you an unhappy camper.

So, that 350 you've found can be a great street motor if you show some restraint and put your plan on paper FIRST. How about a nice low-midrange torque hydraulic cam to start? I love the XE262 grind from compcams. It provides plenty of zip with stock converter and gears but can also respond well to later additions like a taller gear, nitrous, or a set of better heads. Depending or the rest of your build, that same cam can produce from 250hp all the way to nearly 400hp. All while maintaining a fat torque curve and real world streetability on 93 octane.

The point in an ongoing project like yours is to keep your options open as money and time make more things possible. Imho.

build to the drive. street is off idle to 4500 . i use a 262 in street motors. but as said an ls pull out is cheaper than doing a 350 and solves most all problems .

Another routr/choice for a street driver of that era-----the 5.7 vortec from like a 1996------Tahoe---------nice accessory package, best street heads ever from factory, roller lifters, fuel injected and various options in the injector manifolds or even changing to carb----

astroracer , the car had 3.73 gears, a turbo 350 with a shift kit, line lock, electric fuel pump, and will have a good enough stall. And I didn't say I wanted a mid range power cam. I said I wanted a cam with power all through the power band-meaning from idle to whatever rpm. And jerry clayton, I like your idea but I don't hae funds to go ls or anything like that requiring lots of computer work. Sticking to a sbc with carb. Firebird clone, ok thanks for telling me. I'll look for lower lift. But I like noisy timing gears, my dad has them on his built 289. Sounds amazing. But about the vortec engines, I will not be going to a engine that is fuel injected, or computer controlled. Thanks for all the input, appreciated

Originally Posted by 84Monte

I want something with a aggressive lopey sound.

No, you don't.
.

Yes, I do. Why don't I?

You can put a carb on the vortec-you just need an electric fuel pump

and a dist==no computer needed

Maybe I wasn't clear on what I meant when I said agressive lopey sound. Like I want a sound that you would let people know it has a cam, like a choppy kind of idle. And I meant I want to have really good torque taking off and good power up to around 5000 rpm. I've looked at a cam that might fit the description. Thoughts on this cam would be greatly appreciated Part number is Sum- 1069. Advertised Duration 280/280, Lift .443/.443

Oh I never knew that. Thanks for letting me know. If for some reason the 350 I'm getting doesn't work out I'll look into a 350 vortec

Originally Posted by 84Monte

Yes, I do. Why don't I?

Because all the old guys who know better will just laugh at you.
.

Tech will be quick to point out that a lpoey idle is resultant of an inefficiency at idle, and a better focus is true WOT power. For that you need to identify all parameters of the build- tire radius, wheel ratio, cylinder quench, compression ratio for starters. Then you pick the cam AND accompanying components (intake, headders, exhaust) all picked considering peak torque at rpm.

After all that, if you have your lopey idle, bonus.

Pick a can for peak power, not performance at idle.

But that's just a perceived paraphrasing. I might have left something out, or mis represented Tech's perspective.