Im wondering what benefits do you think Id see using some iron L98 heads on a 305 TPI motor? Originally a LG4 but all thats really LG4 anymore is the heads, the rest was changed when converted to TPI including using a roller cam from a 88' 5 speed TPI Trans Am and corresponding stock lifters/roller cam parts. Apparently the heads are the *high swirl* heads...

Is it worth swapping to the iron L98 heads? Or should I just get some aftermarket ones?(price is an issue) I think I can get the L98's for a good price, there is a L98 GTA in a local junkyard that still has the heads on and cam, the reason I ask .

And would the cam be any improvement over the 5 speed TPI cam? Or should I just do a LT1 cam if I wanted to swap them?

TIA

 

It will probably breathe better, because the 350 heads have bigger valves than the 305 heads i think. You may lose a little compression though, cuz I think the chambers are a little bigger.

 

64 cc compared to the 58cc chambered 305 heads. Not much improvement in flow if any.
Heads could be cracked, need a valve job, etc. as well. By the time they are milled down to a respectable chamber size to maintain your compression, you would have quite a bit of money for a small improvement. Basically the same casting except for chamber...

You'd be better off just porting and polishing your 305 heads IMO, and increasing the valve size to 1.94/1.5... Unless you plan to increase the cubic inches later on.

 

Leave the 305 heads on.

With L98 heads, you will have a sharp 90* angle going into the bore around the intake valve, since the chambers have a larger diameter than the bore. The 90* angle is actually the deck of the block.

Also like said earlier, you will lose compression.

 

Thanks for the replies. Are the LB9 heads much better than the LG4 heads?(87 vs 87 lets say). Sounds like if I want to do heads its better off going aftermarket. Down the road I very well may do a 350 swap, but time will tell.

Is the LT1 cam worth swapping over the 5 speed TPI cam? TIA

 

AHHH you cant put 350 heads on a 305 without milling the block for the larger valves. The 350 iron head's chamber is to big for the bore of the 305. You have to deal with serious valve/combustion chamber shrouding. Ported LB9 or Vette L98 Aluminum heads will fit without any milling on your 305. Both have 58cc chamber, just the vette head has a larger intake valve. SR Torquer heads will give a better improvement over the other two. But it looks like the heads you have, may have already had work to it, you just need a better cam.

The B2L/L98/LB9 5spd cam is NOT worth it...thoes cams are flawed by GM because they have to comprimise between money, power, and fuel economy(and emissions). Going with an aftermarket cam like the ZZ4, or LT1 would be good for a fast daily driver and will give you good driveability. Looks like you already have the L98 cam in your engine... LT1 is a good upgrade, but i sugest a ZZ4. either way... they are cheap and can be found easily.

 

???

350 heads will bolt up and run on a 305 as long as you use the correct 350 head gasket. The small 305 bore WILL shroud the larger 350 chamber. There are measures you can take to "help" this problem, but not worth it when your 305 heads will work just fine with a port & polish...or get aftermarket heads for the 305.

The LB9 heads are the 081 heads, which are the same as the 416 heads found on 305 HO motors, and regular low output LG4 motors, except for center bolt valve cover design. If there are other differences I am unaware of them.

The L98 cam is a good cam. The LT1 and ZZ4 cams are not a big step up from the L98, but they are a better design.

 

I cant speak for the LT1's specs, but the ZZ4 cam and L98 cam are WAYYYYYY different. .413/.428 202/207@.050 compared to .474/.510 208/221@.050. Thats ALOT of difference.....and then putting it in an engine with less cubes...it will be even hotter. I dont know about putting the iron L98 heads on a 305......they are bad enough on the 350. Plus, I thought the valves wouldnt clear...etc????

 

Don't bother with the L98 cam, you'll hardly see any gains.

I'd personally recommend World's S/R Torquer heads, that's what I'm gonna go with...I'm also going to buy the ZZ4 cam, I've heard a lot of good things about it.

 

I didnt mean they wont bolt up.. they will bolt up... What I said was that you cant put 350 heads on a 305 because of the chamber size. the L98 heads are a GM comprimise was is the cam.

HA! ZZ4 is not that much different the the L98!!! HAHA! As someone has already posted the specs... you now know the difference... Not to mention the smaller lope for a good rumble, but still streetable idle... ZZ4 cam is a great cam for street/strip performance... and why i am going with it in my 305... just wish i had some money for a decent set of heads!!! Guess i gotta get a good job at school now... dam.

 

The .415/.430 is a good cam. I have it in both of my GTAs. Same cam used in 88 5-speed cars.
Yes, the ZZ4 is a better design. I guess the word "big" in "not a big step" is a relative term.

But with the situation that 4thGenMontes is in, the swap is probably not worth it at this time.

The L98 cam is good for low 13s or high 12s w/ 1.6 rockers and the right setup...N/A

Take it for what it's worth.

Edit: My understanding is that the L98 cam is already in his car.

 

Thanks again for the replies.

So a few different opinions but it seems the cam I have now isnt a huge step down from a ZZ4 or LT1 cam, although not as potent. I figured I should of just got either one instead of the 5 speed TPI one when I decided not to use the 87' auto peanut cam my donor car had .

Also the heads I have are the same as the LB9 I used for parts had too...

So what would be a recommendation for a ok build up using the same 305 TPI motor you guys think, budget wise? S/R Torquer heads/LT1 or ZZ4 cam and maybe some roller rockers? My rear ratio is the stock 3.08 it came with, which I kind of like with the TPI torque and wanting to keep it somewhat good on mileage(ony of the reasons I went TPI).

I doubt Id get to it soon, but something to think about . Gotta build a roller 350 for the SS first . TIA

 

I would get the S/R's for the 305, and get a ZZ4 cam. They are cheap and easy to find. I like the cam myself...as I just put one in my L98. I love the way it sounds......little bit of lope to let you know its not stock. It really helped wake the L98 up...I can only imagine what it would do in a 305 with some good heads........

 

The ZZ4 cam is an all around good cam for the money. You can buy new ones dirt cheap and they perform very well. I love the ZZ4 cam in my TA. It gives a lot of power and a very nice exhaust tone. Like KYL98 said it gives off a little bit of lope but not to the point where it is too much for a street car. Just gives that nice muscular tone that let's you know that it isn't a weak engine I personally dumped my LB9 out of the car and put in what the car has now. More potential for what is planned.