O.k. I have a 68' 400 2-barrel motor that I was thinking about putting a 4-barrell intake and carb. on then I was thinking about putting on my #16 heads with d-port exhaust manifold's.I was told that I should put a mild cam in to.Until next year '05 when I plan on having another 68' 400 out of a g.t.o. really rebuilt for the bird.Now my ? is if I change the heads w/o changing the cam will this weaken the bottom end and by changing the cam will this weaken the bottom end.I want to add a some h.p. to this motor w/o spending alot of $$
Even with the stock cam, the heads will gain you alot of power. The 068 cam will be a good choice for performance with the #16's. May as well change cam if you are changing heads to get the most out of it. Just my .02
I'll go with Steve on that one. With cam and lifter sets from Summit running only $85 (SUM-2801), it would be a shame not to do the cam swap while you've got the whole thing apart. The heads are really designed to run well with a cam like the 068.
if you change cams i would use rhodes lifters to help avoid the pinging. I had some other set from summit and they were horrible. I changed back to rhodes and that solved my problem.
A lot depends on its condition. Normally, if you were looking for a long-term, highly reliable driver, I would advise to go through the bottom end, too. But if you are looking to have a motor for just a few months, and you're not going to put too many thousand miles on it, then there's probably no real problems. It all depends on what you want to achieve. I took your first post at its word - that you are looking to get more out of it for just a little money for the short term only. If you want to build it bullet-proof and get it to last forever, that's another matter.
All the lower end stuff is the same for all motors of that period, including the crank material, rods and pistons - until you get into the Ram Air 4, which had forged pistons and different bearing materials.
If you've got 200K on the lower end and you add a lot of top end horsepower - then, yeah, you might end up with some lower end issues. However, nothing you do will "weaken" what you have there - it will only bring out the weak link in the chain a little faster.
Oh, one more thing what about cam degreeing I've talked to a few people that say with a pontiac it's not really necessary and what exactly is cam degreeing anyway's ?
A little racing, now and again, is a good thing ... don't you think? But remember - your driving habits will have more to do with it than my opinion.
Cam degreeing is basically verifying that the cam is installed and timed correctly. If you have a variable timing system - such as a gear drive with multiple bolt patterns, or a timing chain set with several key ways - it is a means of verifying that the cam is installed and tuned (timed) correctly. Some timing sets can be used with "offset" keys that allow you to advance or retard the cam in increments of just a degree or two. I'm an advocate of altering cam timing as a means of changing the performance of an engine without investing a lot of money in expensive hardware. For the OHC crowd, I have designed and built a variable timing pulley for the camshaft. Once I get some dyno time, I'll be able to post some real world results with it. Milodon already did one for the V-8. It works GREAT.
For the most part, a timing set with one keyway can only be installed one way, so degreeing a cam on a Pontiac is usually not necessary.
It's not all that hard to do. It just takes a few specialized tools and some spare time. For most street applications, it's nothing to worry about. But, if you have a dial indicator and a degree wheel, you should at least try it to see what it's about. (Also, you need an accurate cam card from the cam grinder.)
Last - but not least - keep in mind that I consider street driving to be your #1 priority. Anything else would be another discussion entirely!
Well what I'm looking for is to spruce up this two barrell motor that I have as I stated in an earlier post then I would like to race it in the pure stock musclecar drag's.I was poss. thinking about putting in a ram air cam also instead of the 068.Without touching the bottom end, but while I have the motor this far apart I guess having the crank turned .10 and having new bearings installed probably would'nt add much $$
The motor I have is a 68' 400 I was thinking about maybe using a ram air II cam.So you say the 068 is a ram air cam is it a ram air I ?What do you suggest on the type of cam I should use. Also before this motor I had one that was rebuilt but not hot tanked and when the motor ran the exhaust stunk bad.I was told that it was because the block was'nt hot tanked.Is that true and if so should I have this one done.See the motor is complete and I was'nt planning on tearing the motor all the way down.But if I have to I have to.
The exhaust probably stunk because the fuel was bad, not the block ... just my guess.
The 068 is the Ram Air 1, 3 and 400 H.0. Cam. It's plenty of cam for a 350 with stock heads.
I once had a 041 cam in a 400 engine with #48 heads (similar to your #16 heads), and it actually ran worse than the 067 cam without changing anything else. Once you get headers and some head work done, though, it starts to make a difference.
I can't tell you whether you have to tear the motor all the way down. It depends too much on how many miles, what the oil pressure was at idle, how much it was sitting between the times it was driven, and so on. Far too many unknowns. Basically, I would tell you that if the block stays in the car for a head swap, add the new cam, build it and drive it. If you take the block out of the car, tear it down all the way and do it right. Either way, if the lower end gives out on you because you didn't go through it the first time, you're not really out anything except a little bit of your own time.
That would be cool. I just hope I finish my OHC mods by then. It's a long road, sometimes!
As for your motor: one of my spare motors is a 1967 400 that I was thinking of fitting my #13 heads on. I was going to run a 068 cam in it with a cast 4-bbl. mani and a Q-Jet. That would make it about the same set-up as you are thinking about. All I lack is something to put it into.
