I need to replace my 305 TPI motor in my 88 Iroc. My questions are: 1) Do the L05 heads flow about the same as the L98 heads? 2) What is the COMPLETE cam specs on the L05 cam. My choices are to build my own engine with the parts I have (350, 4 bolt main truck block, 638 casting with roller provisions, LT1 cam, L98 heads) or buy the crate and change the cam. I was leaning towards the crate because it is a lot less hassel than building my own. Thanks, Mike Jones

1.) I don't know that anyone would know the answer to that, since only one person I know of has ever flowed the swirl port heads. That someone would be Dyno Don

2.) http://www.goautocenter.com/350_tbi_1987-9.htm
That should help answer your cam questions.

That's the truck version of the L05, there's also a Caprice version (#12513151) that has a different cam. I don't have complete specs, but according to Pace Performance it has a hydraulic roller cam with 0.360 intake lift, 0.385 exhaust lift, and a 110-degree lobe separation.

The L05 heads mortally suck compared to the L98 heads. They are just about polar opposites as far as stock 350 heads; some of the best flowing, compared to some of the worst.

Your collection of parts is a whole lot better than a replacement nun-mobile engine (the guy that lives in my front yard actually has a Caprice he calls that!!) I would build that a long time before I'd buy that low-performance service part.

if you really dont want alot of hassle, you could get a rebuilt shortblock and put the parts you have on that. It will sure be alot cheaper then the crate L05, which seems a bit overpriced for what it is.

Here's an idea.

Why don't you call Pace Performance Parts and ask them?

Some of you people are so afraid to call these places. WHY? Those people are getting paid to answer questions that they have the answers to. We're not getting paid, nor do we have the answers sometimes.

I have in fact contacted someone from their tech support before and the person I talked to didn't know any more specs than are in their catalog.

Besides, why are you quoting me? I'm not the one who asked the question, I just posted what I knew. I don't even know how you came up with that comment from reading my post.

Are you PMSing or what?

I did call them, I'm not afraid, and they didn't know the answer.

Just asking the knowledgebase here because someone probably knows the answer.

I have been researching here and have heard the following:

- L98 and L05 heads are really close
- L98 and L05 are night and day different
- This crate motor has the L98 cam

That's why I wanted to see the specs. I have seen the incomplete specs on their web site and I have searched the net to no avail!

Thanks...

By the way...

Thanks FLYWAY190, RB83L69 and DIMENTED24X7 for your responses.

I think I may have found someone to build my engine with my parts. For less than 1K he will do all the block and head machining, balance and assemble. He said he would even do some mild porting on my L98 heads. This guy builds race engines, so I think I'm in good hands.

(the guy that lives in my front yard actually has a Caprice he calls that!!) I would build that a long time before I'd buy that low-performance service part. [/b][/quote]


lol theres a guy livin on ur front lawn? i'd run em off with a shotgun.

The reason I quoted you is because you're the person that said the LO5 mich2112 was looking at was for a Caprice. If so, then he he/she should have said that. My response wasn't directed at you, it was just convenient to quote you.

And to mich2112,

I understand you thinking I'm pissed but I'm not. May I remind you that I was the first to respond to TRY and help you, but YOU didn't supply enough info for me to be able to help thoroughly.

I gave you unopinionated responses (unlike others here), to the best of my ability. I'm sorry the waahoos at Pace don't know their chit. That's very unprofessional IMO. Even if they didn't know or have the info in front of them, they should have taken your name and number, called GM, found out, and called you back.

Even though you made it a point to post this...
..... and exclude me, the next time you need help I'll try and look beyond your sarcasim and help you regardless.

I have to disagree with this, respectfully of course. I have rarely spoken to people from the various performance parts suppliers that know what they are doing. The same seems to be true at the local speed shops. I find that typically out of the 5 or 6 guys at the local shops one will usually know what the hell he is talking about. Sometimes it blows my mind what people who are paid to give advice will tell someone.

The advice I have seen on this site is without a doubt some of the best I 've seen from anywhere.

And as far as low performance crate motors, it really seems like a rebuilt short block or having your own done is a much better deal for what you get.

No I didn't, go back and re-read my post. You covered the possibility that he was referring to the truck version, and I added that info in case he was referring to the Caprice version. I was also taking into consideration the possibility that mich2112 didn't know that there was more than one version of the LO5.

I was referring to part number 12513151, which is the Caprice motor. The guy at Pace didn't even seen sure it would work in a TPI Camaro.

AJ_92RS:

I did appreciate your first response, but you posted the other on me before I could clarify. Making the assumption that I had not called them or try to find the info before posting here. Did not appreciate that.

I thought this forum was for technical discussions and not slamming members.

Thanks...

......

:sillylol: Actually, he's about a quarter of a mile away, in front of the lake that's in my front yard.... My house is a well back from the street, and there's a whole row of houses along the street, in front of my yard.

haha yeah i kinda figured i just thought it sounded funny at the time.. also i was a tad drunk.

I'm going to second what RB83L69 said about the heads. They are the worst heads GM has ever made (performance wise). Anyone who tells you otherwise has never looked down the intake port of and LO5 or an LO3 head. If they HAD done so, they would tell you to avoid it too.


As for the cam, I dont' remember the exact numbers, but "flyway190"s numbers seem about right. I know the lift is LESS that .400", and that's terrible.

If you buy the LO5 long block, be prepared to go buy a cam AND heads to make it worthy.

Thanks Tom...

That's what I wanted to know.

Wow!
I am not sure I really want to reply to this post.
This is a little long so read on or skip to the summary.

Anyway I cracked the heads in my old 87 TPI 5spd about a year and a half ago. At the time I knew nothing about this board
and even less about the engine in my car.

I called locally about rebuilding the 305 and eveyone quoted me over $1k. I found Pace Performance surfing on the web. They have great prices on crate engines, but no 87 5.0 F. I called them and they reccomended the caprice TBI 12513151. They also said that I should replace the cam with an LT1 Cam to increase the performance. The said nothing about the heads.

I had the engine and cam installed by a "trusted" auto shop. I have had the worst problems because of the install, not the engine or cam. The car runs great and is much much more powerful than the original 305.

I have since burned a new prom to adust for the larger engine and 24bs injectors i have installed. I run TTS Datamaster all the time and record changes to prom, timing etc. It clearly shows that I run out of power at about 4.5k. On the other had I have tons of torque.

I plan to install vortec heads using the SDPC manifold and change the cam and runners. I not interested in track, where the short runners are definitely better. I will definitely post the horsepower and torque curves for the swirl port heads and with the vortec heads so people can see the difference.

Summary
The LO5 crate engine is a pretty good engine and even with the swirl port heads its faster then the 305s. The LT1 or even the LT4 are good cams to put in this engine, but they are designed for STR and not optimized for the TPI LTRs. If you don't have a good speed shop you trust, then buy this engine and replace the heads and cam like I did. Attached is my latest dyno.

With the water under the bridge I'll post some pics.

I have some of the 193 heads so you can see how they're designed. I should give you a better understanding of why they're NOT good RPM/HP heads.

I still say... Using a stock TPI I made 295HP (250 RWHP) with these heads and a little cleanup port work and an LT1 cam. So.....say what you will, but that ain't half bad for supposedly junk heads. It would take a he** of alot more work to get the same out of a pair of 1083's.

BTW: The car ran 13.70@101

Don,

Did you cut out the "ramp"?

I know you have actual experience with these heads, that's why I informed Mike and told him your name.

He must have PM'ed you, right?

Anyway, everytime you talk about what you've done, I get so giddy about it I forget to ask you questions.

As you can see, I'm porting the heads, and I just want to know if there are any areas you concentrated on more than others. It would save me A LOT of money to get these heads "good enough for now", until I can afford something else.

Sorry, I don't mean to highjack this thread. It's just cool that Don has actual FACTS about these heads, and not an .....

Perhaps I'll PM you (hell of an idea, don't you think?) and get more info from you.

I am having a hard time with this statement. You would think it to be the other way around

I found it. :rockon:

After a 1/2 hour of searching, here are the flow numbers of the 193 heads that Dyno Don said he messed with.

http://www.thirdgen.org/techbb2/show...hreadid=177465

He said he didn't spend a lot of time porting them so I imagine the ramp (or whatever it's called) was left in.

Don?

http://us.f1f.yahoofs.com/users/db5b...zExP_AGujiTmfG

I didn't remove the swirls just smoothed them out.

These are flow numbers from a SuperFlow flowbench on a pair of 193 LO5 heads. I input the numbers into Desktop Dyno 2000.

I have the caprice lo5 in my car. I should have went a different route. Even the cheapo GM crate would have probably been better. Oh well Im getting sportsman II heads and a XE270 cam so I should be ok

Let me put some things to rest...I too was "giddy" after the Dyno numbers, but read this thread first...

http://www.thirdgen.org/techbb2/show...threadid=97882

Basically it will take you a few hours to make the 193's flow the same as untouched 083's.


Could be hogging out the vane would make the 193's more compatible to the 083's, not sure...definitely not gonna mess with it either.

Ok, I'm just wondering why we don't see more L98 Camaros and Firebirds running mid 13's and making 250HP on the dyno. Their cam isn't that much different than a LT1.
What I found on the 083's is what has been gone over many times, the intake roof is way to low to be a good flowing head for making power (hence the 15 and 18 degree racing heads.) Better line of site to the valve.
But hey, if it works more power to ya.
I'm certainly not advocating running out and grabbing a set of swirl ports, but if you already have them and are adventureous, have some fun and go for it (porting them).
Don>>>

http://us.f1f.yahoofs.com/users/db5b...zExP_AGujiTmfG
Try this it worked for me.
I made this up on Dyno 2000 from the #'s off of the Super Flow bench.

Here are the #'s in case the link doesn't work for you.

Intake
.050-40.
.100-70.
.200-115.
.300-139.
.400-180.
.500-196.

Exhaust
.050-29.
.100-49.
.200-105.
.300-137.
.400-163.
.500-177.
@28.0 in H20 1.94 In. 1.50 Ex.

Thanks Don.