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OK I did some searching and founf some info, but I still have some questions. I have a GM crate motor, and the block numbers cross to a gen1/ZZ4. Its pretty sure its not a ZZ4 because it has the iron heads. I recently put on 1.6 roller rockers and am getting ready to get a ZZ4 cam for it. I dont want any problems down the road when I do this. I read about taking out the pressed studs and putting screw in ones, guide plates an some other things. What else should I look for, is that necessary, do I need to replace rods or springs? The engine has less than 40,000 miles so my seals should be good, other than the ones am going to be breaking loose during tha swap. Am I asking for trouble, or should this be fairly painless?
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__________________ 91 RS 350 Ram Air TBI Auto
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Flowtech terminator "muffler" w/ open exhaust
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Hedman headers & y-pipe
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Projection 2" bore TBI base
650 TBI
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Comp cams 1.6 roller rockers
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You will need to find out what heads are on the car now. Grab the casting number from the top part of the head (requires removing the valve cover) and cross reference it at www.mortec.com. If you have junk heads you won't get much out of a cam swap. Screw in studs are always a good idea because pressed in stock ones cam pull out with high lift cams. Stock heads are also cast with cam lift limits of .460" to .480". You would need to have the guides cut to safetly run a high lift cam.
The key to your set-up will be chip tuning. I see you have the hypertech programmer which in its current application is terribly miss-matched to your combo. Your car is in dire need of a custom tune and a new cam will only require it further. Without it you will only be making your car slower.
OK I checked the casting numbers and came up with 14102193 which crossed over to 87-up...305/350......1.94"/1.5" valves. Which doesnt give me a lot to go on. let me know if you have more info on them. As far as comparing them to some of the other valve sizes they may not be all that bad.
Those are the 350 TBI heads. As-cast, they are less than desirable due to the swirl port design they are 'cursed' with. Good for low end torque (like a truck would need), but anything above about 3000 rpm and the ramps become a flow impedement.
I would look for new castings, since machine work is already needed for them to even work with the ZZ4 cam and 1.6 rockers. If they were mine, I would not invest the time, nor the money, into making them work. I would look for a set of 305 castings (416, 601's) and work those over if you are on a budget.
Things that would be required, though, include milling the guide boss to allow for more clearance between the bottom of the retainer and the top of the valve seal (you should also consider having them machined for positive type valve stem seals). Machining the stud bosses for screw in studs and guideplates is also a wise move, or, at the least, pin the studs. Valve spring pockets MAY need to be enlarged, depending on what valve spring you decide to go with.
Do you have any other specifics besides the valve diameter? Im playing around with desktop dyno and want to plug in the right numbers. Also how can I find out which cam is in it now? The block number is 10243880, which crosses to ...350...95-00...2 or 4 bolt main...Vortec truck, Gen.I crate motors and "ZZ4", roller cam, one piece rear seal. Dont know if that helps, but I got the motor out of a salvage yard nearly brand new. It was an Old lady that had it put in her Caddy right before it got rear ended and totalled. Now, I know where I can get a set of 416s for 20 bucks, but what will I have to do to them and will it be worth it?
On the other end of that what cam can I go with to not have to do all the milling and still get a good power gain. If the heads are going to make a huge difference I can swap them also.
Sounds like it (the engine) is a generic drop in replacement motor (think commercial van/truck engine).
TBI heads, I wouldn't work with them as a base, unless you do have plans to remove the swirl port ramp. There are better castings to use as a base head (such as the ones I mentioned earlier)
About all you can fit under the factory heads is a cam that is equivalent in lift to something such as the Comp Xe262. I ran an Xe256 in my 305 and it worked great. Considering the block, though, I would stick with a factory roller design. The ZZ4 cam would be a direct swap in.
I would really consider having some 305 heads worked over for the apropriate hardware and then do some DIY port and polish work. They have smaller combustion chambers to begin with (cast as 58cc versus the 193's 64cc) Between that and the rest of the combo, you could have an engine that performs on a very similar page to the ZZ4 engine. Do a search for Sitting Bull's thread. There is a bunch of good info in there. Likewise, F-BIRD'88 also has a bunch of good information floating around, might want to try a search under his name as well. And yes, the power increase with worked over heads is well worth the time and effort.
416's are the 305 carb heads. 305 TPI heads are, casting wise, almost identical. After porting and whatnot, they will turn out the exactly the same- result wise.
Of the two, which are better, they both seem to be about the same, but the valves are smaller than the ones I have on now. Is that going to matter much, or can I have those milled out?
416's were also on '82-'83 crossfire, and '85-'86 TPI 305 engines.
I agree, sounds like you got a truck or Caprice LO5 replacement engine. If you go with the 416 or 601 heads, you should have them machined for 1.94" intake valves, and if budget allows, 1.60" exhaust valves. The chambers should be deshrouded if necessary, and if at all possible, have the valve bowls cleaned up (sometimes called "bowl work", other times "pocket porting" at machine shops). I'd also suggest having the valve guides cut down for installation of positive type valve stem seals - 2 benefits to that: 1) better seals, and 2) more clearance for more cam valve lift. Of course, the studs should also be improved to handle additional lift, and new aftermarket valve springs.
I have the 416 heads on my camaro. I had the valves radiused and had some exhaust bowl blending done. So far they have been great. The only thing holding me back is the cam. I chose a cam that is way to small (.404/.415 202/207 14.5).
The only other issue I had was the pre-87 bolt pattern. Other than that they have been good.
OK if I went to the U pull yard snooping around for heads, are the 416 0r 601 the best? Of course I know if I get lucky enough to find aluminum ones to grab them but if there is a better head I want to know.
601 has a slightly smaller chamber, (52vs58cc?) fast355 will probably chime in, and mention they worked great on his gi-normous van... sitting bulls porting heads thread was about 601 heads. 601 heads are usually found on trucks and vans.
Otherwise they're similar.
No need to worry TOO much about compression ratio right now. You should try to figure out what the compression ration is with the 193 heads. Due to the engine probably being a generic drop in, I'm willing to bet 8.5-9:1 range. Either way, you'll gain roughly a point of compression between the 64cc's of the 193 heads compared to the smaller chambers of the 305 heads (obviously the 52cc of the 601's yielding a slightly higher compression increase over the 416).
What I did was take 4 lengths of screws all heat them and bend them upward so that they come out of the heads and go stright up. Then the intake manifold will sit down right on top of them. Then just bolt the manifold into place. My buddy James came up with the idea and it works just fine. Might sound kinda hokey but it worked great. Been two years now and works fine. No problems. And it was pretty easy.
We posted some picturs but I can't seem to find them.
Originally posted by exdog OK I checked the casting numbers and came up with 14102193 which crossed over to 87-up...305/350......1.94"/1.5" valves. Which doesnt give me a lot to go on. let me know if you have more info on them. As far as comparing them to some of the other valve sizes they may not be all that bad.
The valves aren't bad, nor are the heads --- they just aren't performance heads -- and neither are any of the prior GM production irons heads... until the issue of the LT1 in 1992.
What do you want from the engine? If this will be mostly street driven, and if the engine and heads are nearly new (with unworn valve guides, and more importantly already paid for), then remove the heads and port them using DIY effort. You shouldn't need any more machine work done on them unless you plan to run a big cam (above .460" lift).
There is no reason to remove the swirl ramp -- it has a worthwhile use and it doesn't have to be an impediment to airflow -- but you do want to smooth the ramp edges and do some bowl work. Backcut the valves if they aren't already and remove the rotators on the exhaust valves and replace them with regular GM retainers and locks from the iron LT1 or L31. All of this is inexpensive... which is my reason for suggesting you look into it.
See this thread (read the whole thread) for the reasons why. Tradeoff Fast355's results vs the cost and performance gain by using another set of heads that might requite some added machine work. HTH.
EDIT: if you did get a Caprice replacement engine, then the engine will have the so-called peanut cam. You'll probably want to replace it. The LT1 Fcar cam is a cheap suggestion that will still work fine with the stock rockers, and there are enough people here running it to get opinions from. A new hyd roller cam will otherwise cost you over $200.
