Hey all, as most on here might know, I don't know much about engines. But recently have been having some work done. I started by ordering the LB manifolds from RARE, which I had been wanting to put on my car for some time, and also ended up ordering the X exhaust system with spintech mufflers for my convertible threw them also. After talking to my mechanic, he told me I should change the heads and maybe the cam also.
After reading on here I asked him what the changes to the heads and cam was, since he usually just does not tell me things, probably cause he knows I would not understand
He told me the changes to the heads should give me around a 9:1 compression ratio? if I am repeating him right. And that he installed a 280 Cam. He also replaces the pushrods, that he showed me and they were not in good shape, and mentioned the lifters I believe, but I can not remember if he replaced them also.
He told me he may have to change the Torque converter, but he would not know until he started the engine and rove it some?
I am really just posting hoping to learn What changes were made, and if everything sounds right to everyone on here? Also how this all should change my drive? obviously it will, but really I have no real idea how much.
Right now my engine is just sitting there outside the car, with the heads and cam replaced, and just waiting for the LB manifolds from RARE to get to me (they are very slow about shipping them it seems) and my mechanic figured it may be best to put them on the engine before putting the engine back in the car.
Sounds like he knows what he's talkin' about. You should have good power and still be able to burn pump gas. And it also sounds like he's familiar with getting the most power out of your new set-up with a new torque convertor. Smart mechanic!
Thanks for the response, yea that really what I was looking for, he is a old guy, and very good with old cars, but I still like to make sure everything sounds right. He would never touch a computer to use the internet, so does not have the benefit of learning through so many knowledgeable Pontiac people as on this site.
He told me he would be able to drive the car and see if the current torque converter would work ok, or if it needs a new one to run the engine right.
Those look sweet. I would talk to your mechanic and ask him of he can install. It is not a job I would want to take on. There is some expertise required to make sure it does not get fubared.
If you car is a weekend cruiser and not long hauls I would look at 3:73, with a 2800 stall and your combo it will give you that OMFG.
A new cam has to be broke in. He will need to run a good oil. The mechanic should have some large fans to place in front of the car, and will run it at 2500 rpms for 20-25 minutes. Then drain the oil and check for copper or metal filings. He should also pull the filter and cut it open and check for metal as well. If all looks good then the cam is good to go.
I would look at Crane, Crowe, Isky, or Lunati VooDoo cams.
All of this is null and void if you are running a Hyd roller cam
Another thing, if the heads he took off were the original ones for your car, be sure to keep them. Otherwise you may just be kicking yourself years down the road. Or maybe not, if you don't care about originality, or if they were very common and easy to find heads.
Vikki 1969 Goldenrod Yellow / black 400 convertible numbers matching
Yea the engine is not the original 350, it was out of a Bonneville I think I found out The guy at RARE (Paul I think) told me that they were probably out of a '72 since the heads were missing 1 of the bolt holes, he said that 72' was a GM strike year or something, and they cut corners? Anyway my mechanic did not replace the existing heads, he sent them to someone else local that did something to them the change the compression I guess, he also drilled a hole in each of the heads for the new LB manifolds will have all 6 bolts holding them on
Thanks for thinking of that anyway Vikki hope you doing well.
Sounds like he had the heads shaved for more compression. Ask him if he installed adjustable rocker arm nuts, you'll need them. Also, you might ask him about the condition of the front pump seal on your transmission. Now would be the time to change it.
I finally got my LB manifolds from RARE, long story there. Here is a good picture of the silver ceramic painted LB manifolds, I have seen pictures of the gray on here before, but thought someone might like to see the silver ones.
Hopfully this will work well with my 350 car, with the new exhaust and the heads bored out etc... Ill let you know in a couple days how it sounds and drives, hell Ill take a video and stick it somewhere so you can hear the exhaust.
BTW when I first asked him what the specs where of the CAM he installed, I swear he told me a 280 cam, but I can not figure out any reason why they above CAM would be called a 280 cam at all from looking at those specs?
Hey guys, I need to ask a couple of questions about my new exhaust. I guess my car never had the convertible middle brace on it, I always thought people were talking about that brace that goes over the end of the transmission.
My new exhaust has already been installed, and from the pictures can anyone tell that if I ordered a brace it will actually fit on here? over the X part of the new exhaust? my thoughts are that it would not.
The guys that I had install it, said it was not easy and someone that could not cut pipe and weld would have had major issues.
Also I told the guys to cut the ends coming out the back over the rear axle off short and add chrome turndown tips out the back, I am almost wishing I would have just left the full 2.5" pipe out the back with them bare maybe, what is mosts peoples preference? I am just not sure.
It doesn't look like the brace will fit. The best way to have your exhaust done is by having the cross brace installed and have the shop fab the exhaust.
As for the tips I have mine turned down at about 45 degrees just past the rear tires. Hope this helps.
Hmm those are the exhaust set fram RARE, not sure why they did not fit better, I know most of you are more for getting the exhaust localy custom done, but really thought these would still fit better, either that or something was installed wrong?
BTW thanks for those pictures Vikki, I printed them out, going to take them in to the shop, cause no one understood what I was trying to say. 1 pictures worth 1000 words!
Vikki, is that one of your cars? Wow, that looks like a nice clean install!
Yes, that's my yellow 'bird. It took about 5 hours to get that fit, but the shop wasn't going to call it done until it looked just right. They even ovalled the tailpipes as the originals.
Vikki 1969 Goldenrod Yellow / black 400 convertible numbers matching
My new exhaust has already been installed, and from the pictures can anyone tell that if I ordered a brace it will actually fit on here? over the X part of the new exhaust? my thoughts are that it would not.
It will not. It's way too low.
68' Firebird 400 convertible, numbers matching, solar red w/ deluxe parchment interior. 66' Pontiac Ventura Hardtop 66' Pontiac Catalina Convertible
Would have to check my cam cards at home, but looks like the "744" RAIII M/T cam. Be pretty radical in a low comp 350 with A/T. Better in a 400 with 10.0 + c.r., 2800 stall, 3.42/3.55/3.73 gears.
What are the raised casting #'s on the center exhaust ports just above exh mans? If you want extra clamp load for your exh manifolds, Spotts Performance has brackets that bolt to front and back of the heads and over the ends of the mans.
And if you want to use the convert brace, find or make spacers to put between it and the body. Think "Pypes Performance Exhuast" makes a kit.
That would bring the X brace pretty close to the ground with all that pipe sitting under the belly. And it's pretty close to the "041" cam profile too. Seemingly a lot of cam for a 350 auto. Let us know how it goes.
Vikki 1969 Goldenrod Yellow / black 400 convertible numbers matching
At 224/236, I would call that too much cam for a 9:1 350 in a 3600 lb. street driver. The 115.5 lobe separation helps a little, see how it drives. You could add a converter or some gear to get the torque back to where you would be without it, but why? For this deal I'd go about 204/214 max. That's about 10 degrees more than stock. In my experience 326 and 350's without gears do not want much cam. DJ
1969 Firbird 400 Coupe, 11C build date. Liberty Blue, TH400, A/C, P/W, posi, Rally II
As soon as I get it back I will let you guys know how it drives, it should be done today or tomorrow.
Most the the information about the cam is just plain over my head, I do know they also changed the torque converter.
Given what Jim mentioned above, what is the real world results of having to much cam in a 350 car like mine? so I would know what to look for when I drive it?
The cam's not a huge issue, it will probably do okay. What you will get is a slightly rough idle and less low end response. It will feel a little soggy when you stab the pedal from a stop. Anything above 30-40 mph the effects are less. Your mechanic's not doing you wrong, just sounds like he's from the older school of thought. In today's world of low compression and crappy gas, "putting a cam in it" just doesn't get you much. Drive it around and see how it is, try to advance the timing as far as it will take without pinging.
1969 Firbird 400 Coupe, 11C build date. Liberty Blue, TH400, A/C, P/W, posi, Rally II
Tuff crowd. I'm just go'n from memory. Have used all the RA cams 3-4 times each helping other guys build engines.
Was being gentle earlier, but will say now you wont like the 744 cam in a small valve/low c.r. 350. And need at least a 2800 stall with 3.55-3.73 gears.
Pontiac identified all their cams with 7-digit part numbers. Usually, they are referred to by their last 3 numbers. In this case, the "744" cam refers to Pontiac's Tri-Power and Ram Air 3 Manual Transmission camshaft. As far as I know, it was dropped during 1969 in place of the 068 in Ram Air 3 motors.
I'll try and keep it simple cause i have a hard time explain'n it.
The 226/234 duration #'s are the degree's the valves open and close in relation to crankshaft rotation. Higher the #, the longer thier open.
The factory low perf cams start about 210. Every 10 #'s higher rises the rpm power range "about" 200 rpm's. But you also lose the same amount at the cams starting power range. Doesnt sound like much, and isnt till you get to 225, then you need more gearing to get engine into higher power range. Generally the smaller the bore and stroke of the engine, the more gear you need to accelerate vs a larger bore and stroke engine.
Then there's lobe separation. It complicates things. Generally the wider(112-118) the lobe sep, the milder the engine idles, and it also has a smoother, wider power band. 104-108 lobe sep's have a narrower power band, and idle ruffer. Especially in a small bore/stroke engine. 110-112 lode sep is a good compromise for idle quality vs power band.
A 224/236 cam in a 350 gives a ruff idle with high end power, but with a low end power loss. In a 455(larger bore and longer stroke), it idles fine, and the power level will be lower. There's more to it then what i posted, but hopefully this gives you good idea.
Also the BTC-ABC-BBC-ATC #'s have ALOT of influence on how a cam acts. Just grinding the same 224/236 with different BTC-ABC-BBC-ATC can make it more aggresive, or milder. That one is on the aggresive side vs the 068 cam even though thier very close to overall duration #'s
Thanks for all the good info Poncho, I will get the car back sometime soon, Ill let you know how it drives I guess. I really dont have much to compare it against, and not really to sure what to expect, will be very interesting. I am nervous, I hope I dont hate it.
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