camaro87-alex

Hi there...
I have a simple question when it comes to cylinder valves.

I am going to change camshaft on my engine so I am gonna buy a new camshaft with new springs and retainers ++ for the Heads.

My engine is a 87 305 TPI engine. The engine was original a 305 LG4 but I did a TPI swap last year.

I was thinking of changing the valves on the cylinder heads since I am going to take out the heads anyway.
What is the stock dimension on the intake and exhaust valves on a 87 Lg4 engine?

And here is my main question. I was thinking of buying bigger valves from Summit. They have some intake valves that is 1.94" and 2.02".
If I buy one of those, would they fit in to my valve seat?
I mean. Is the valve seat big enough to handle those?

The same question about the exhaust valve's though.

hope you understand what I mean. My english is not perfect since it is not my Main language, so it is a little hard to explain...

New2Chevy

iTrader: (11)

Did you do a complete engine swap or just put tpi on top of your Lg4? If it's a 1987 Lg4 beneath, your compression ratio is 9.3:1...something to keep in mind when you choose your camshaft. First off, stick with the 1.94/1.50 valve combo in your heads, which is stock. Remember....it's a 305 with a smaller bore than the 350. Even if you built your 305 to 400 hp, you'll never need bigger valves than 1.94/1.50. While you're at it, you may want to ditch the stock heads (they are terrible, in my opinion), and get a set of vortec style heads milled down for 60cc combustion chamber (or even smaller cc, if you have Lg4 bottom end) and with better springs, and get a vortec-specific manifold (http://tpiparts.net/inc/sdetail/2944). Make sure you get your lobe separation on your camshaft as close to 115 as possible because you're going to be tuning with tpi....tpi loves the lobe sep. If you ignore this rule, then I say, "Have fun," to whoever tries to give the darn thing an optimal tune. That's my advice...take it or leave it.

Atilla the Fun

305 heads never came from GM with 1.94" intake valves, though you can upgrade to them, if you take your heads to an automotive machine shop. 305 heads came with 1.72" intakes in the late '70s, and 1.84" in the '80s and '90s.

camaro87-alex

Ok..So the stock dimension is 1.84 on the intake??..What dimension is the stock exhaust valves?...

What does it takes to upgrade the valves?..To change the valve seats or is it possible to machine the stock valve seats??

camaro87-alex

Are the stock heads really that terrible?..I thought that if I gave them a "rebuild" and got them ported and polished and mayby some bigger valves on them they would perform good...I just thinking of money also because all of the parts I am going to buy is very expensive to ship to Norway so I need to think extra on what I am buying..

Atilla the Fun

Greetings to Norway, my mom's late ex was from there. Anyway, unless your heads are cracked, which doesn't seem probable, there's no need to buy others. I assume you have a "local" machine shop that can rebuild automotive engines. I've rebuilt hundreds of 305s, I'm an automotive machinist by trade. For 305s, the main reason for going to bigger valves, aside from performance, is to run better valves. Stainless, 1-piece valves. These can be ground down to 1.84", but it makes more sense to cut the heads. If you need better valves, you also need more flow. Stock heads with stock valves are fine for 250 crankshaft HP, and 5000 rpm, with an occasional trip to 5500. And they're okay for an additional 50 hp hit from nitrous oxide. Stock exhaust valves likewise. They're 1.50". The shop should be able to recondition your stock valves, if you wish. If you'd like to upgrade, look at this: http://www.competitionproducts.com/p...sp?number=8430 and whichever way you go, have the shop put a small 30-degree back cut on each valve. get the valves all finalized before the shop starts on the valve seats. Stick with 45 degree seats, and have them adjust the width of the seats using 30 and 60 degree angles. Lastly, if they're equipped to do so, have them follow up with 75-degree cuts down in the bowls. If you want power, or live at high elevation, or have high octane gas cheap, or especially any combination of these, run flat-top pistons, not stock-replacement dished pistons. I'll need more info before I can suggest anything else.

d4nk

iTrader: (2)

I know a lot of people are thinking the same thing. I've been down the road of trying to build a 305 and it just wasnt worth it. I went with the aluminium 56cc trickflow heads and a voodoo cam only to be disappointed. I would suggest saving your $ and go with atleast a 350 block.

camaro87-alex

Thank you very much for responding so fast and explaining so understandable. Hope you can give me further information in the future so I can communicate with you more.

I know I don't have explained anything about my engine yet.
I can tell you this information:

My car was a stock 305 LG4 engine that I converted to TPI last winter. This conversion included: Stock intake manifold, stock runners, stock plenum and stock fuel rails.

The fuel injectors were remanufactured and ALL of the sensors are brand new. Spark plugs, Rotor and Cap, spark plug wires. All of those are brand new. The MAF sensor is a used one but is in working condition.
I got this Air-foil on my throttle body so the flow should be mayby a small % bigger there...

Like I said it was stock a Lg4 engine with 170HP..yeeeeah

Now I want to have more power...And I am not talking about a race car of 400HP but closer to 300 should be perfect.
I have ordered a lot of tuning and chip burning equipment from Moates and I am studying this a lot so I am going to burn my own chip so I don't need to think of that when choosing parts.

My engine has runned about 85K miles so the engine is not at all broken.
I want to re-use my heads because I think it is not necessary to buy new one's when they are only 85K.

Here is my setup:

Hooker 2055HKR headers

COMP Cam 08-302-8

Catco 9118 Catalytic converter

Port and polish my stock heads

New valves with retainers,locks +++


So far this is my setup. I am going to start on it as soon as the winter is arriving to Norway because then the snow is falling down and with our BAD roads around here it is not any good to drive a rear wheel car with a V8 engine in it.

When it comes to the engine block itself I have thought about changing the pistons. Will they help me get any more power or torque?

You are talking about a machine shop. Unfortunately I have to send my parts to the closest one because the closest shop are MANY miles away from here...But that is possible of course..

Atilla the Fun

okay, why remove the heads at all? better to leave them on. new valvesprings, yes. New valveseals, yes, but those are no more difficult to do with the heads still in place, and removing them is a real pain if the engine is still in the car. If you're concerned about retainer to seal clearance, that's what "plus fifty" locks are for, and not only are they far cheaper, they're no extra work if you're doing springs and seals anyway. That cam is okay for a TPI 350 with a 3.27:1 axle, but it's not a good choice for your 305. By the way, is your transmission an automatic, or a manual? For a TPI 305, you're looking for a cam that will build great torque below 4800 rpm, so I suggest you install a COMP 08-408-8, especially since your compression is low and your TPI components are stock. Even an 08-412-8 would be a better choice. As for valvesprings, 100 pounds on the seat is plenty. With only 85,000 miles, you shouldn't need any machine shop work at all. And until you buy some better TPI parts, porting the heads isn't pressing, as the TPI flows less than your heads, unless you have the '88-'92 305 heads, in which case, you do need to buy better heads.

New2Chevy

iTrader: (11)

I just think the Vortecs are worth their weight in gold, when a guy is trying to make some power on a budget. Vortecs love the cubes, too, so swapping them to a 350 later is a sound idea. If a guy's totally broke, keep the stock heads. Lots of good information here...sorry about my error on the valve sizing...I'm getting 1.94/1.50 on the Vortec heads, which is very close to the factory size. That's what I should've said earlier...sorry, I was in a hurry to get ready for work. I believe it's better to buy a set of Vortec heads than spend almost as much money getting work done to factory 305 heads (porting, etc., etc.). You may spend a bit more money getting new assembled heads, but you're getting MORE for your money, IMHO. $830.00 for a set of assembled Vortec heads, for a 305, that can also be swapped onto a 350 later is not a bad deal (even if you spend more $$ later to get the 2.02" valves for the 350), especially when many guys will be happy with a 350ish horsepower 305, until they can build something bigger, if they ever want to do so. That's just my opinion. Too bad we're not all rich, so we could build 700 horsepower LS1s and swap everything out and do it all at once, tranny, rear end, driveshaft, etc., etc. That would rock.

camaro87-alex

Ok..You see my plan was to take the whole engine out of the car when the winter comes. The reason why I want that is that I want to repaint my engine bay because most of the paint in there are starting to look very bad.

And when I am going to take out the engine anyway I was thinking of a rebuild.

I see you have mentioned those two camshaft I have been looking for a long time now. I have this Camshaft Quest program from COMP cams so I got a few good tips there. If you look at this 08-412-8 Camshaft, I see that the lobe seperation is 110. Isn't that a little low for a TPI engine?..Just curious about that.

So what do you suggest I should do?..Should I do something about the heads or should I just leave them alone?..I mean, is it worth the money to rebuild and port them and that stuff?

You see I am going to make a shopping car from summit racing. I want it to be as finished as possible so I can order all the parts I need at one order. Much easier to send it that way..

camaro87-alex

I have actually been looking for a while on the vortec heads, and I must say I am thinking of buying those. But then again the amount of money beeing used is raising. If I buy a pair of Vortec heads I also need a intake Vortec intake manifold that fits my TPI. That would also cost...So actually I am just scrathing my head here and asking "what should I buy??"..
Not a easy choise...The only thing I want is more HP and torque for a reasonable price. If I can get close to the 300HP range I will be very happy

AlkyIROC

2.02/1.60 valves won't fit inside the bore of a 305.

New2Chevy

iTrader: (11)

I thought that was established, but maybe it wasn't?

New2Chevy

iTrader: (11)

The stock 305 heads are restrictive, and I don't like them, not if a guy wants to make 300 horsepower or more. I would get the Vortecs and a cam with larger lobe sep and good lift. Trust me, it's easier to tune a tpi optimally when the lobe sep is as close as possible to 115, so 110 is pushing it a bit, in my opinion. 112 would be better than 110. You want to maintain good vacuum pressure, too, ya see. You can use the vortec heads and the vortec manifold, if you ever get a 350, too, or you can sell them to someone, if you decide to go aluminum some day. Some guys might say, "Ah phooey to that," but it's true. I'll post a good cam in my next posting, when I find it.

New2Chevy

iTrader: (11)

Here's one from Comp Cams. XR264HR Lobe seb 112--Lift .488/.495--Duration 264/269 (212/218 @ .05"). And here is one that I may be going with, which is hard to beat for the street and pushing well over 300 horsepower--Comp Cam XE268H--110-.477/.480-224/230 at fifty. I am doing away with tpi and changing my entire fuel injection system, as well as swapping to Vortec heads, while I get my 383 built. I'm still researching cams for my application. I'm seriously considering Comp Cam 268XFIH13 type cam... 113--.520/.515--224/231 @fifty. That would be a nice little grind for a 305 OR a 350.

Atilla the Fun

You said you are going to burn your own chips, for tuning your engine, so that gives you some flexibility with the cam. Lobe separation is not an issue, overlap is. With big cams, wider lobe sep, like 115, helps reduce overlap. your stock EFI is looking for at least 15.5" of idle vacuum, and both cams I mentioned will do better than 15.5. Back to overlap. The cam you listed has 9 degrees of non-overlap at 0.050", while the smaller one I mentioned first has even less overlap, at 11 degrees of non overlap. That helps idle and mileage. The larger still has 5 degrees non overlap, thus will also pass an emissions test and drive well. That's less overlap than some of the larger cams, with wide 114-degree lobe separations, sold as being for TPI engines. Remember, you're using stock TPI parts, you need a cam that builds torque below 4800 rpm. Also, if you do get Vortec heads, you're going to lose even more compression, and that's bad. You'd need to either get flat-top pistons, or have the Vortec heads milled. back to the cams. You want an early intake closing, for 2 reasons. 1 is your limited rpm range, the other is for your compression. And even if you choose the larger of the 2 cams I listed, it'll still have the intake valve fully closed sooner than the cam you listed. As for whether the vortec heads are worth it, as long as you stay with your stock TPI tubes, even if you change the lower intake, they're not worth it, because your stock TPI tubes aren't flowing enough air, even for your stock heads. If you really want 300 HP, you can toss the TPI and build a Vortec-headed 305, or you can put a 50-horse hit of nitrous on your 305, or you can do the smartest thing, and order a Vortec-headed 350, and the matching lower intake, and some aftermarket tubes, but that's getting into big money. If the car spends 50% of it's use at a racetrack, then you'll end up with a 350 anyway, sooner or later. But if the car lives on the street only, then just build a smooth-driving 305, and add nitrous.

305sbc

iTrader: (3)

https://www.thirdgen.org/forums/tech...rings-l98.html

link to some valve swap info

New2Chevy

iTrader: (11)

Well put. Good stuff for the guy keeping tpi. Since I'm changing my entire FI system and intake setup, I'll have more freedom, which is what I like.

camaro87-alex

Woow...Really some good information here. It really helps me out a lot actually. I think I will go for one of the cams you have mentioned then. I am really thinking of this COMP cam 08-412-8. Think that sounds like a good one.
I know people are talking a lot on changing engine to a 350 because then it would be easier to acheive the goals I am in to when it comes to HP.
But as you also mentioned I am not focusing only at the HP rating because since I have a TPI system I should focus more on the Torque rating.
I don't think I want to change engine now because my stock engine has only gone about 85K miles like I mentioned. And to me it sounds bad to take out that engine and throw on another. Mayby later when I have more miles on the engine but not now.
I think I also have forgot to mention that my car is a daily driver that is most used on street.
When it comes to nitrous here in Norway that is really a thing people are not using. I don't want to say anything bad about nitrous but it is just not used so much here in Norway. And to me it feels like fake HP on the car. Almost like steroids to the engine. So I want to have real HP and torque that the engine itself are producing with regular fuel.

I think I would go for a setup like this then:

Hooker 2055HKR headers (those can be used on a 350 in the future also)

COMP cam 08-412-8

Catco 9118 Catalytic converter

New valve springs,retainers,seals and keepers and that stuff.

New burned chip that is fine tuned to the specs.

I also want to change gears to something like 3.43. I have 2.73 now


What I really want is just a car that has good acceleration on the streets.
250HP is also enough so don't get me wrong here. But my car is not more that 170HP LG4 engine now with a small camshaft. And when my friends around here come with their cars like Audi, Vw, BMW, with engines about 1.8 litre. And are almost accelerating faster than me that has a V8, then I get a little frustrated...So I think I would go for the setup above...
But thanks a lot for the help here. This is one of the best threads I have made I think. The information is just marvelous.

New2Chevy

iTrader: (11)

In a month or so, I'll post up dyno results for my 305, and I'll list my mods, too.

camaro87-alex

Thanks..I appreciate that..Would be nice to see what results you get.

New2Chevy

iTrader: (11)

No doubt. I'm excited to see what I can make the 305 do.

Atilla the Fun

I think the 3.42:1 rear axle gear ratio is the perfect choice for what you're doing. I'd suggest you do it before starting on the engine. Also, install a new Auburn Gear limited slip differential, and Richmond Gear's "mega" install kit, which includes new axle bearings. Also, new synthetic gear lube, all of these are available from summit racing. When the UPS or FedEx truck arrives with all your new stuff, you'll remember Christmas morning when you were a kid. Getting new parts which you need, that feels good, but getting the whole truckload, of parts you want, that's better than $ex.

New2Chevy

iTrader: (11)

Thanks, and I agree, and I hope that my car is one of the 86's that has the G92 option (3:42s). I don't have the car yet, and it's 300 miles away, and I have been DYING to get the dang thing and check it out. It's in way nice shape, especially for an 86.

mnorton

With an 87 TPI (because of the LSA) you'd be better of with this cam, but the lift is a little too much for stock heads.

08-501-8

New2Chevy

iTrader: (11)

Comp Cam 12-466-8 has much higher lift and will require heads to be worked on (I'd just get the Vortecs) and also a 2600+ stall, but the lobe sep. is 113...even better. I'm really considering the 12-246-3 for my ride, though. I'm swapping the entire fi system and intake, though, along with the heads. Also, the flow numbers on the RHS Pro Torker Vortecs are higher than any other Vortecs I've seen, and they're only about 100 bucks more than the EQ's. I'm going with Manley valves, though, because they are superior to the Comp valves. Since I'm gonna have it all apart, I might as well put better stuff in it.

camaro87-alex

Hmmm...I looked at the CamQuest program from COMP cam, and you are absolutely right about the LSA. And the lift is about the same as the 08-412-8...Mayby I should go for this cam instead...

And I am going to upgrade my valve spring so they can handle bigger lift

New2Chevy

iTrader: (11)

As far as heads go, I think the difference in flow numbers between these two Vortec heads is noteworthy. I'm definitely going with the RHS heads. Granted, the bore will be smaller than that which was used for the test on the RHS chart, but they will still flow better than the EQ's....worth the extra money in my opinion.

EngineQuest Vortec Head Flow Chart

Lift/ Intake Flow/ Exhaust Flow
0.1/ 60/ 54
0.2/ 117/ 102
0.3/ 173/ 134
0.4/ 216/ 152
0.5/ 225/ 162
0.6/ 232/ 169
0.7/ 237/ 172


RHS Pro Torker Vortec Head Flow Chart

New2Chevy

iTrader: (11)

http://www.strokerengine.com/VortecHeads.html I found this interesting, too.

New2Chevy

iTrader: (11)

So, have I convinced you to go with the Vortecs? To me, it's money well spent, for torque and power, when you get good flowing heads that will maximize a more aggressive camshaft.