Either I'm real stupid (most likely answer) or my head casting no. is not on any pubished list. I think the number is 10090574 - '89 305 RS. The heads are going into the shop tomorrow for cleaning/magnaflux/valve job - any recommendations?

 

Never heard of that one.

You SHOULD have 14102187. That's what everybody else has anyway. Which my recommendation would be, if that's what they are, don't spend a dime on them; throw them in the trash, and get a set of 14101081 (87-up TPI/L69/LG4 305 heads) instead.

 

That's a WEIRD casting #. See if your machinist can verify WTF it is I guess.

 

Is that the number between the valve springs, under the valve cover?

 

It is 14102187. Any one know where I can get the other heads mentioned by sofakingdom (14101081)?

 

off a 305 TPI 3rd gen camaro/firebird.

you can use 416 heads as well, you'd just need new perimeter bolt valve covers. These are on all 305's made after '82 or so, until mid '90s I think.
Pretty common

601 heads are on trucks and vans with 305s. Smaller chamber, some say superior chamber design. Either way, they'd work as well.

 

I would stick with the 187s.

 

ANYTHING BUT the 187s.

This same guy posts this same thing every time anybody mentions those garbage heads. I think he's just hoping that he'll talk some of these people into leaving their cars crippled by those things, and that they'll be in the other lane someday when he's at the strip.

 

haha, yea what, and beat them in his 15 second van? I dunno sofa, i'd sure hope a halfway respectable 3rd gen, even with swirl heads, could beat the van, like boy, I hope so...

No offense Fast, I think your ride is cool, i'd put crushed velvet in it and make it a *******-wagon though, but that's just me. And never keep candy in it, that's just a lawsuit waiting to happen
Supercharger working well?

 

And this SAME guy post this same UNSUPPORTED claim every time these heads are mentioned. Get some scientific proof to back you.

Crippled by 187s, HAHAHA. The exhaust from the head ports back is much more restrictive. The peanut roller cam follows this. The heads will be perfectly adequate until a touch over 300 HP, in STOCK form. 400+ HP if their inadequacies are worked out.

Superchared 350 TBI is running well. The 4L60E took a dump though.

 

300hp untouched? I'd have to see proof of that to beleive it... No offence, I usually agree with you on alot of things, but not this time. 300hp without touching anything is asking ALOT from a swirl port head, especially on a 305. 400hp with all the inadequacies worked out? That could be said for most factory iron... double humps, swirl ports, HO heads, TPI heads... They all need the same work to remove their 'inadequacies', but the TBI heads also have that cute little ramp to deal with on top of that. And forced induction changes the whole game, especially when dealing with cylinder heads.

 

Lo-tec ran 13.61@ 101.5 mph with a 1.91 sec 60' time, using a junkyard Cadillac LO5 engine (193 casting swirl port heads) that he installed into his 3rdgen. The thread is here.

In that thread Lo-tec wrote:

That's not quite as quick as an LT1 4th gen (275-285 fwhp), but it's close on both trap speed and ET especially given the very good 60' time. So it's not unreasomnable to estimate his output at 250 fwhp... and that's using the 214/220 cam posted above.

Would a hotter cam, like the GM LT4 HOT cam, with more duration and lift, have made the car run quicker & faster? I think it's safe to say yes. How much quicker/faster? I'll guess 0.2 seconds quicker and +2 mph. So that would put the engine near 270+ fwhp. It's not 300 fwhp, but it also getting close.

How close can you get? (i.e. Fast355's comment of 300+ fwhp from unported swirl port heads). OR, what is the limit of hp through stock unported swirl port heads?

If you believe people like Vizard or Lingenfelter, they've written that for a 350 v8 the fwhp max is roughly the peak intake airflow in cfm*2.0. Stock 193 casting swirl port heads flow around 170-178 cfm when free of cooked oil residue. That would put a ceiling on fwhp of 340-356 fwhp, understanding that you'd need a big cam and a good exhaust to get that far. That's exactly what Fast355 was talking about.

What many people here cannot get a grip on (and probably never will) is that there are two paths to engine power:

1. airflow through the heads as measured by intake and exhaust airflow (in cfm flow vs lift),

and then there is:

2. combustion (burn) efficiency (which can be viewed by looking at the minimum spark advance needed to make optimum WOT power).

A head can flow very well (like an old hemi head) but not have good burn efficiency (needs 42 deg spark advance) and require high octane fuel (because the burn characteristics are poor). A head can also flow poorly (stock GM heads from the 1980s, which include swirl port heads) but have very good burn characteristics (less than 30 deg advance), and have very good resistance to detonation. In the case of the GM heads (either swirl or non-swirl from the 1980s), neither needed to have big flow numbers because they were relatively low-power engines (up to 210 fwhp on the TBI with swirl ports, up to 230 fwhp on the TPI 350 used on Fcars). A measure of good burn efficiency also shows up in the BSFC (brake specific fuel consumption) but people seldom measure it nevermind understand what it means.

LT1 and LS1 heads do well in both categories. Swirl port heads, unported, do very well in burn efficiency but not in airflow. Airflow can always be improved (in any head) by porting, but it's very difficult to alter the burn characteristics of a head. That's why it's not a waste of time to port a swirl port head, because gaining airflow while retaining most of the swirl is a winner at all engine speeds and loads. On an older oper-chamber head with a recessed spark plug (like 416s), you can gain more airflow but the combustion doesn't really improve so the gains are not as much as they would be on the faster burn head.