TPIMonteLS

iTrader: (1)

I have a relatively stock TPI 305....its a 87' LG4 block with a 87' TPI setup and 88-89 5 speed TPI cam, headers/catback exhaust with a K&N filter on 88-89 Trans Am intake elbows. The heads are the LG4 heads which I do believe are the same as the LB9's.

Im thinking of getting some aluminum 90'+ L98/ZZ heads and with porting/head work, Crane Gold 1.5 roller rockers(fit under stock covers) and either a LT1/ZZ4 cam. Custom PROM to delete the EGR function and maybe help with other mods too.

How much power would these mods yield, and what is thought of the combo? What cam would be better with the rockers/heads, the ZZ4 or LT1?

I do want to keep it under a budget(ok the rockers ain't cheap ), hence the using of GM parts, not a $250 cam or $600-900 heads . I have a set of 86' aluminum Vette L98's but would rather get the D-ports....or does that matter much?

bigals87z28

sounds good. Im going with teh ZZ4 cam its bigger then the Lt1 and would go better with the zz4 heads.

D Stroy H8

I think you could see low 14's.. This isn't really a build up persay, and more a smattering of improvements on a TPI 305. I am not to sure what the difference is between the LG4 and LB9 shortblocks... so I assume they make similar power with the TPI and TPI cam. Go with the ZZ4 cam, and the ZZ4 heads. That is a no brainer there.

RMK

If you are going to the expense of getting the Crane Gold rockers, get the 1.6s. I have them and they fit fine under the stock valve covers.

As for the cam, there a a few different LT1 cams out there. Just make sure you get one of the better ones.


Robert

TheMysticWizard

iTrader: (1)

Can you swap an LT1 or ZZ4 cam right into a 1987 TPI 305?

Is there anything special needed, or is it just a swap of the cam?

bigals87z28

nope, nothing needed. I belive on the Lt1 you need to file down a tab or something, but thats it.

wyclefsirocz

I don't think LG4 heads and LB9 heads are the same. but i might be wrong, I'd check into that. i know they are a swirl port design head unlike the LB9. so I do not think they are the same. Also a *** set of slightly ported LB9 heads w/ 1.94 valves would some pep to you car

bigals87z28

i forget what year, but the LG4 had teh same heads as the Lb9.

SLP IROC-Z

iTrader: (1)

wouldnt bother with the aluminum heads, not worth it, theyll just shroud. you'll be much better off getting a pair of LB9 heads, preferably 89+, having the bowl work done, gasket matching and exhaust port massaging. these will yeild the best power gains. and puttina 1.94 valve in them is a waste of time, again it will shroud and you wont see anything out of it.

so basically:
89+ LB9 heads
bowl work
gasket matching
exhaust port massaging
stock valves

for the cam the LT1 is ok but uve already put in the L98 one so whats the point, u will get sometihn out of it but id go with the ZZ4 over the LT1. check out comp, i called their tech line and they recommend to me a 114 218 224 .449 .452 cam to me its pretty decent for the 305. for roller rockers go for comp magnum rockers, 1.6s.

bigals87z28

SLP IROC, Im gunna have to go ahead and dissagree with you there, the 1.94 valves will not be shrouded by the bore and you will see tremendous gains if you did that along with angle job on the seat and valve. And whats so important about 89 and up?

87 B4Z

werd

SLP IROC-Z

iTrader: (1)

i wouldnt say tremendous gains from a "modified" lb9 head, maybe 25 flywheel hp if your lucky, the 1.94 will shroud the bore and shroud the side of the chamber. the edge of the valve is to close to the edge of the chamber the flow is not good. as far as ive heard there is a few variations of the LB9 heads, differnt cast #. ive seen no proof of to the differene of the centerbolt ones. but my guess is GM didnt go backwards if they made changes, so if it was me id try to find the newest LB9 heads i could, make sense?

SLP IROC-Z

iTrader: (1)

"this is a 305 head with a 1.94 in. valve in, notice how close to the chamber wall the valve is...that is called valve shrouding. the airflow doesnt like to go thru that too well"


"A 1.94 valve is every bit as close to the bore as it is to the chamber too... in otherwords you can't fix shrouding by porting the chamber."

this next pic shows a 2.02 valve in a 305 head just for ****s and giggles. for those of you that cant see the problem with the 1.94s this is more of a exagerated view of the problem.

bigals87z28

Ok good cause I was setting you up for this...

Then how does World Heads get away with putting a 1.94 intake valve on there SR 305 Torquers? It says 30hp gain. weither thats fly or rear I dont know. Why would World sell heads that wouldnt be "direct bolt in" as per Worlds advertisements? And if you say because they dont want a lot of lift, they have springs installed to hold up to .550 lift. I know its tight, but Im pretty sure you can get away with it.

SLP IROC-Z

iTrader: (1)

i just gave you more then enough facts and pictures why using a 1.94 valve has no benefit in these heads. you wanna know why world products uses 1,94 valves in their 305 heads. this thread is a good example why, because people like you will look at them and go "wow, i can get a 1.94 valve and its gonna give me 30hp, im gonna buy those" you think world doesnt know that if they used the stock valves that people wouldnt buy them because they felt they werent getting anything differnt then stock. also world says up to 30hp in their advertisement, under that it has every single head they make for all differnt engines, so dont try and say that world says a 30hp gain for their version of the 305 heads, we both know thats BS. all the world product heads are are a cleanerr casted head (hense why they can claim any power gain because they flow slightly better) and their ever so great 1.94 1.5 valve configuration (note sarcasm)

5SIZ

I personally would want Vette alum. heads. For the price they can't be beat, aside from vortec heads and for a certain year they made a 58cc chamber vette head instead of 64cc so it's a direct bolt on for our 305's, too bad I don't remember the casting no.

bigals87z28

Ok.. well then I better finish this convo off....


My friend had World 305 heads on his 305 and had no problem with shrouding. Not only did he have any problem, but he ran 11's? (with spray of course). He is a member of this site. His name his Badass305(or something of that nature) I belive you have heard of him. He now has a 434 small block.

SLP IROC-Z

iTrader: (1)

well hows this sound. i know another guy on this site by the name of Tim Burgess that runs 11s in his 1992 305TPI 5spd Z28, actually a best of 11.69 @ 117 on ported stock lb9 heads, stock valve sizes a TPIS super profile cam, 3.45 rear gears, stock weight as well and a 125 shot of juice. oh yes with out the 125 shot he runs high 12s. oh yeah... stock TPI as well

SLP IROC-Z

iTrader: (1)

the casting # for the 58cc aluminum L98 heads is 113, their also used on the ZZ4 crate engines. not exactly a direct bolt on persay, in order to get full potential of these heads the compression ratio has to be raised up to 10.25 - 10.50 : 1. since aluminum heads dissapate heat a lot quicker then irons do the compression ratio has to be raised up to maintain the same chamber temperature. there is some work required to raising hte compression up with these heads, the thinnest head gasket that can be had for a 305 is a composite .041 gasket. this means machine work has to be done to the heads and with a final 0 deck height. i quote this from F-bird88 in a prior thread.

"Use flat top pistons. Forged is a good idea for a Squeezed motor. get the deck height and quench area right before you worry about shaving the head.
With a .040" head gasket you want a final 0 deck height.
You'll have to get the pistons and measure them in the block
to know for sure how much decking will be required.
**** Approximate*******
Every .0065" shaved off the heads will remove 1 cc
**** Approximate***
on your motor with 5cc flat top pistons at "0 deck height",
and a .041" gasket I would shave the heads to 53cc's
(about .030") I would shave .025" off and then cc the chamber to check it first. Then you'll know what final cut is required to get the final cc you want.
Its all about detail and checking.

this will give you 10.45:1 compression"

5SIZ

Tim is a friend of mine, and SLP's description of his setup is accurate.

But let me just say that Tim is the most **** retentive man I ever met He set everything up on that motor to the T, every gasket was matched, every injector was balanced, EVERYTHING was perfect.

bigals87z28

ah i see how that proves the valves are shrouded huh?

SLP IROC-Z

iTrader: (1)

well Al, ive done my fair share with facts in this thread. if you are still ignorant to the fact, then i cant help you further. if ur friend has 1.94 valves on the 305 there is shrouding going on if you want to beleive it or not. i have to lol @ "My friend had World 305 heads on his 305 and had no problem with shrouding" i mean honestly did u go inside his engine and look? as you can see from the pics i posted there is definite shrouding with the 1.94, deny it all you want it wont change reality.

my reply about Tims car was to prove that the stock valves are sufficient, and that ur friend isnt running 11s just because he has 1.94 valves. it can and has been done with the stock sizes.

TunedPort 335

I just took a pic of a spare set of "081" heads I got. These have the 1.84/1.50 valves. If you need anything bigger than a 1.84 intake valve on a 305, you shouldn't be messing with a 305 at all. I think 1.84 is plenty sufficient for the RPM's and power that built 305's will see.

Here it is -

Tremo

Has anyone tried to put a 1.6 exhaust valve into an LB9 head?

Tibo

iTrader: (15)

I have the World Torquer S/R cylinder heads on my 305 and I can show you (math, dyno, seat of the pants, stuff I broke after I installed them,you pick one) that the World's are a 30 hp gain.

Yes there is shrouding, SLP you proved your point. But is it to the point that it will hinder or not produce anymore power? Ab-so-freakin-lutely Not! No one has also mentioned that a cam with more lift and/or duration will also help out tremendously with valve shrouding issues. No one has also mentioned that they are supposed to raise your compression by one half of a point.

In my opinion the ALUMINUM PORTED Vette heads would be as good as the stock UN-ported IRON World Heads. But with a good cam and port job the World's would be better.