[Kevin]

I have a stock 1967 400 with the factory 670 heads from a GTO, it is the base motor that was originally paired with a TH400. I believe it has an 066 cam in it.

I would like to be able to run pump gas, I would also like to have a little more cam than the original and keep as many stock parts as possible. I may add a set of headers.

With the compression of this engine what would be a good cam choice for this engine?

Thanks in advance,
Kevin

[TransAm 474]

With a mostly stock high compression 400 like yours, the Crower 60916 would be an excellent choice. With the TH400, I would run a 3.23-3.42 gear with it. It will have great street manners and should tolerate pump gas easily. If you wanted something a bit bigger, with a little more sound at idle, you could run the Crower 60243, along with Rhodes lifters, if the slight tick of the Rhodes wouldn't bother you. Regardless of camshaft choice, it would also be a good idea to have you factory distributor recurved for the correct timing and curve. We have Cliff Ruggles recurve our distributors

[TransAm 474]

If you are on a budget, the Summit 2802 with standard lifters would also work well for you. Just make sure you use a good USA made lifter, such as Hylift-Johnson from Topline Automotive. Memeber "Paul K" here on the forum is a dealer for them, that is who we purchase from. I would suggest avoiding ANY offshore lifters, in which most are these days.

[promptcritical]

Originally Posted by Kevin

I have a stock 1967 400 with the factory 670 heads from a GTO, it is the base motor that was originally paired with a TH400. I believe it has an 066 cam in it.

I would like to be able to run pump gas, I would also like to have a little more cam than the original and keep as many stock parts as possible. I may add a set of headers.

With the compression of this engine what would be a good cam choice for this engine?

Thanks in advance,
Kevin

It’ll have alot of compression with flat top pistons. Maybe too much for comfort with pump gas?

[25stevem]

Are going to stuff in a new Cam and just run the stock high mileage valve springs , because that's like adding sour milk to a fresh cup of coffee?

[TransAm 474]

Originally Posted by promptcritical

It’ll have alot of compression with flat top pistons. Maybe too much for comfort with pump gas?

It will work fine on 91 octane pump gas, as long as the timing and fuel curves are in check, and the proper camshaft is used. Alot of people get scared and drop compression on these engines, because they automatically think you can only have 9.5-1 or lower compression on pump gas or it won't work, but that is not true at all. As long as the correct camshaft is chosen, along with the timing and fuel curves correctly calibrated, it will be just fine, and will be a noticeabley stronger running street engine than the one with dropped compression. The 3 camshafts I recommeneded above should have zero problem working with pump gas at his compression in a 400.

[promptcritical]

Originally Posted by TransAm 474

It will work fine on 91 octane pump gas, as long as the timing and fuel curves are in check, and the proper camshaft is used. Alot of people get scared and drop compression on these engines, because they automatically think you can only have 9.5-1 or lower compression on pump gas or it won't work, but that is not true at all. As long as the correct camshaft is chosen, along with the timing and fuel curves correctly calibrated, it will be just fine, and will be a noticeabley stronger running street engine than the one with dropped compression. The 3 camshafts I recommeneded above should have zero problem working with pump gas at his compression in a 400.

Yep. I didn’t say it wouldn't work. Just have to be aware of being close to the edge. I run 10:1 on an iron head 455 in Arizona heat with the crap gas we have available. It works fine. Just have to be careful bringing the timing in loaded at low RPM. I try to keep it running relatively cool water temp too.

[MarkS57]

My 400 w/ high compression 62 heads (open chamber) ran very well on pump gas with the 068 cam. The 670's are closed chamber which might play into this. I also ran 93 octane not 91.

[TransAm 474]

Originally Posted by 25stevem

Are going to stuff in a new Cam and just run the stock high mileage valve springs , because that's like adding sour milk to a fresh cup of coffee?

I agree with Steve, you will need to install new set of springs with whichever camshaft you use. The Crower 68404 spring is a good replacement spring that will install at factory Installed Height. just be sure to watch the clearance between the bottom of the stock retainer and top of the guide at max lift. If you don't have sufficient clearance, you can take .050" or so of the bottom off the stock retainers to gain clearance.

[TransAm 474]

Originally Posted by promptcritical

Yep. I didn’t say it wouldn't work. Just have to be aware of being close to the edge. I run 10:1 on an iron head 455 in Arizona heat with the crap gas we have available. It works fine. Just have to be careful bringing the timing in loaded at low RPM. I try to keep it running relatively cool water temp too.

Oh yeah, for sure! I didn't mean to imply you were saying anything wrong, I was just throwing it out there for future readers, as there are alot of people out there who are misguided by the "9.5-1 compression max on pump gas" theory.

[promptcritical]

Originally Posted by TransAm 474

Oh yeah, for sure! I didn't mean to imply you were saying anything wrong, I was just throwing it out there for future readers, as there are alot of people out there who are misguided by the "9.5-1 compression max on pump gas" theory.

[chiphead]

Another vote for the 2802. It'll want at least 3.23 gears and a mild stall for optimum performance. It makes enough vacuum for power brakes. Use with the crower 68404 or Comp 988 spring with a set of crower retainers. Look for my thread about it here.

[Kevin]

Originally Posted by 25stevem

Are going to stuff in a new Cam and just run the stock high mileage valve springs , because that's like adding sour milk to a fresh cup of coffee?

I have no problem with installing new valve springs if that’s what’s needed.

[jhein]

Question for TA474, or anyone else. You recommended Rhodes lifters for the 60243 but not for the 2802. They are very close on duration, lift is a little more on the 60243 and the LSA is different. Is it the tighter LSA of the 60243 that would call for the Rhodes, or something else? Just trying to learn. Thanks.

[TransAm 474]

Originally Posted by jhein

Question for TA474, or anyone else. You recommended Rhodes lifters for the 60243 but not for the 2802. They are very close on duration, lift is a little more on the 60243 and the LSA is different. Is it the tighter LSA of the 60243 that would call for the Rhodes, or something else? Just trying to learn. Thanks.

It is due to the 114° Lobe Seperation of the 2802 vs the 112° Seperation of the 60243. The tighter Lobe Seperation of the 60243 will produce a little less vacuum, and the Rhodes lifter will help gain that back and idle a touch smoother. In all reality, the 60243 camshaft in a 10-1+ compression 400 would probably be fine with Standard lifters for most, and still produce plenty of idle vacuum for power brakes.

[Jay S]

For running more compression with stock parts in the heads, stock valves, seals, splash guards, ect… it might be a good idea to consider a Melling SPC-3 cam, (a reproduction of the RA3 744 cam. It is comparable .050” durations to the summit 2802 but has a wider LSA and less lift, (.407”&.407”, versus the 2801 and .466”&.487”).. A bit bigger than an 068.

I think though with 1.5 rockers the lower .407” lift limits the Spc-3’s potential some, and it is going to be much friendlier than a 068 for higher compressions on pump gas. But if more cam was needed for the combo, running 1.65 rockers on the spc-3 for .447” lift would be a step in the right direction. Still pretty safe with stock components. Intake pusj rod clearance with 1.65s should checked. Usually it clears, but with 1.65s it is close. With the stock valves, valve seals and splash guards the 1.65s are not an option with the higher lift cams like the 2802 and the crowers. If it was a fresh build with new stainless valve and posi seals I would certainly look at the higher lift cams though. Depends what the engine has now.

It would be interesting to see a comparison of valve curtain area between a 2802 summit with 1.5s and the SPC-3 with 1.65s..

[b-man]

The base 335 hp 1967 GTO 400 came with the 067 cam, automatic or stick.

What rear end gear?

What transmission will you be using? We know the engine was originally attached to a TH400 so is that what you’re going to use? If automatic are you using a stock torque converter or a higher stall unit?

What car is this going in?

Headers or exhaust manifolds and if manifolds standard log style or Ram Air/HO?

Carburetor and intake you’re using?

What octane pump gas? Depending on where you live 90, 91 or 93 are usually what’s available at the high end.

All pertinent information to help decide what cam to use.

[Kevin]

I plan on using the stock 1.5 rockers.

The car is a 67 GTO. It will have an automatic, stock converter at this point with 2.93 gears.

I have the original stock log manifolds and a set of headers on hand.

It will have the stock intake with a q-jet.

The engine is out of the car, I plan on cleaning it up, replacing seals and gaskets and then painting the engine before reinstalling. Performance of the car isn't a concern, I want to make this a rolling resto. I don't have a problem running premium gas in the car but having to find higher octane fuel would be a deal breaker. The original cam was/is very boring, so I was thinking changing the cam could be a win/win/win by making it friendlier with current gas, maybe make a little more power and maybe make it sound a little better too. This car hasn't moved under its own power in 25 years.

[tom s]

JMO,any cam with that rear end gear is going to be boring.Best bang for the $$$ for the ass dyno is lower gears.3.42 would make a huge diff and wont kill you on the highway.Tom

[Kevin]

Tom, I agree with you. I have a set of 3.55 gears and a posi for it that I can install later. Right now I'm going to try to get the thing running again before I tear into something else.