Hi guys, I need to know what the difference is between the two following heads:

1. 14101083 (1987-88 350 TPI F body) same as 14101093 for -- 1989 TPI F body 1.94/1.5 valves, 64 cc chambers
2. 14102193...87-88 Chevy Caprice (also trucks, which I assume were TBI)...305/350......1.94"/1.5" valves, 64cc swirl port chambers

The TPI head is also a "swirl port" design, no? I'd like to know if there is any performance difference between the F body 350 TPI heads and the '193 Caprice/truck heads

 

083's are not swirl ports and can be made into good heads, 193's are swirl ports and can be made into scrap iron. The "swirl" is not in the combustion chambers, it is in the bowl just under the intake valve.

 

The chambers are not swirl port on the 193 heads -- it's the shape of the ramp under the intake valve port that induces swirl. The 083 heads lack the ramp, although the port volumes between the two are similar. The chambers of the 083 and 193 heads both have deep insertion plug positions to promote fast burn, and the shape of the chambers surrounding the valves is also designed to somewhat unshroud the valves and promote swirl and therefore fast-burn.

The TPI heads were not swirl port designs, though the chamber shape does induce swirl. The 193 heads get swirl inducement from both the intake runner and from the chamber shape.

As far as performance differences, here's some detail on the stock flow data of the heads (L98 TPI heads: 083 iron and 113 aluminum; LO5 TBI head: 193 iron). The following is a brief version of a longer post in another thread:

Stock head peak flow numbers in cfm along with the 3rdgen source for the data:
083 iron L98 head: 185 intake; 106 exh (smithtc)
083 iron L98 head: 194 intake; 118 exh (rhuarc30)
083 iron L98 head: 202 intake; 141 exh (F-BIRD'88, note that he says: "I get much higher numbers. Have so on numerous different sets of like heads". He was probably commenting on ported heads but his stock 083 numbers suggest a similar trend)

113 alum L98 head: 199 intake; 149 exh (Chevy High Performance)
113 alum L98 head: 182 intake; 145 exh (Vizard book, p124,127)
113 alum L98 head: 193 intake; 162 exh (GMHTP)

193 iron LO5 head: 178 intake; 146 exh (Dyno Don)


Note the trends. 083 iron heads (L98 Fcar) have the same intake port as the 113 heads (L98 Ycar) so the intake flows are similar (with F-BIRD'88 as the exception). The 1986-(early)1988 aluminum head exh port was also the same as the 083 exh port, so the 083s flow the same as early Vette alum L98 heads.

083 iron heads have a different exh port than the 113 alum heads (D-shape anti-reversion exh port) used from mid-1988+ Corvettes, so the 083s don't flow as well on the exh as the 113s. GM revised the 113 casting in the late 90s (when they re-tooled the casting, per the GMPP website) which explains how GMHTP and CHP got much better numbers recently than Vizard did circa 1990.

The stock 193 heads flow better on the exhaust than the 083 heads, and almost as well on the intake side as the 083s. That's contrary to numerous "opinions" provided by many TGO "experts". Since you can't fully use the intake flow if the exhaust is weak (because it doesn't fully clear the cylinder) then you could say that the 083 heads have self-EGR, at least more so than the 193 head do. So the 193 heads are as good as the 083 heads in stock form because the intake flow is almost as good, and the exhaust flow is better.

With that said, all the above heads can be ported. The 083 and 193s have more meat on them so they can be ported more and withstand more abuse, while the 113s are not as durable but are much lighter. So improvements in airflow can be had on all the heads.

If you set aside the flow numbers, and look instead at power and torque of the engines as they were rated by GM, the differences between the Fcar L98 engine (083 heads, 220 fwhp first year) vs the 9C1-version of the LO5 (with 193 heads, 205 fwhp and both use the exact same L98 cam) it would seem that the 083 heads are better than the 193 heads by 15 hp --- but the intake manifolds are also different (TPI vs TBI).

Dyno Don once did a TBI/TPI test on a 305 engine (as discussed elsewhere in another post -- use the search). Dyno Don got measured a 19 peak hp difference on the same *305* engine, after swapping the TBI for a TPI. After correcting for temp (two different months tested), the gain is more like 13 hp. 13 hp difference on a 305 would be 15 hp on a 350, which is exactly the difference on the GM L98 iron 350 TPI engine vs the GM LO5 iron TBI engine. So the difference in output is due to the intakes, not due to the heads, either based on actual power output (GM figures or Dyno Don's tests), or based on looking at the flow differences among stock heads.

The heads, 193 vs 083, are physically different within the intake port but not nearly so different in terms of airflow, stock vs stock. The flow numbers of ported heads (also shown elsewhere on TGO if you search) show the same results that would be typical for small-port volume heads. Neither the 083 nor the 193 (or the 113s for that matter) will flow like more modern aftermarket heads (AFRs for example), or even the newer GM heads like the ones on the LS1, but then again both the 083 and 193 heads were designed almost 20 years ago for use in passenger cars (and trucks), during a time when a 15.0 sec car was the fastest domestic vehicle sold. HTH.

 

kdrolt, thanks so much for this very helpful information! Do you know if the 193 head is the same chamber size (64cc) as the 083 head? I have found conflicting info as to whether the 193 are 64cc chambers, or much larger

 

193 iron casting was 64 cc, so that the static compression ratio was above 9:1 (but below 10:1) when used in light trucks (C/K) or in fullsize cars (B and D platform) and so that it would run on 87 octane. IIRC the static cr was 9.3 to 1 on the LO5 used in B/D cars.

It would be helpful to find out whether the other swirl-port truck 350 head (I think I read this on the Mortec website, 191 casting suffix?) had larger chambers. The only reason to have a larger chamber would be to keep the compression ratio low so that a lower octane fuel could be used, or when used with raised profile piston, also to keep the cr in the designed range.

The 083 head would have had the same volume to get the same targeted static cr. The 113 head (the aluminum L98 head) got the smaller chamber so that the static cr would be raised, as a way of making up for the extra heat loss into the aluminum head (aluminum transfers her much better than iron does). GM did the same thing on the LT1 aluminum head used on F/Y cars: they had a quarter to a half point more cr than the iron LT1 used in the Bcars.

 

Thanks kdrolt. Do you know of any flow #s for the 305 TPI heads, the 416s (early) and the 081s (later)? Also, is the only difference between the 416 and 081 heads the angle of the center intake bolts (are the ports the same fast-burn style and the ports the same size?)

 

AFAIK, from reading here on TGO, the 416 vs 081 differences are the angle of the intake manifold bolt hole and the way the valve covers attach to the heads (perimeter vs centerbolt).

For flow data I have what follows, listing each by casting number suffix, RPO code for the engine, and peak flow numbers in cfm for intake and exhaust, along with the source for the info. The usual caveats about peak flow vs partial lift flow apply:

Stock 305 heads, 1.84"/1.50"
187 iron LO3 head: 165 intake; 140 exh (Fast355)
081 iron LG4 head: 195 intake; 110 exh (ME Leigh)

Ported 305 heads
416 iron head: 220 intake; 161 exh (Kitch, 14014416)
081 iron LG4 head: 221 intake; ??? exh (ME Leigh, stock 1.84" diam int valve)
081 iron LG4 head: 230 intake; ??? exh (ME Leigh, 1.90" diam int valve)
601 iron heads: 224 intake; 157 exh (Fast305, 1.84/1.50, 14022601, medium duty truck heads)

The 187s are swirl port heads from the 305. I don't have any ported data for them (yet). I expect that they would flow similarly to the ported 193 heads, because the 187 vs 193 data (stock vs stock) is similar: 178/146 cfms for the 193 and 165/140 cfms for the smaller intake valve 187.

The rest of the heads are along the lines of what you were looking for. The above was collected from TGO sources, and the link to each source is in my post within this thread. The thread is approx 2/3 of the way into the topic (Garage ported 193's flow numbers). HTH.

 

Thanks so much kdrolt, your help was worth everything to me. I picked up a pair of clean 416 305 heads for $25 each, installed new valve springs and seals and hand lapped the valves, and voila, I have 10:1 actual compression with the 58cc chambers and my forged speed pro flat top pistons in the 327. The car still pulls to peak power past 6000 rpms and is very responsive. I sure have compression now -- I have the total timing backed down to 32 max WOT from 38-39 where I used to run when I had 8:1 compression. I may have these heads cut for 1.94 intake valves over the summer and hog them out a bit, but for right now I should be able to finally get this heavy car / small engine combo into the 13s , since I have my tune pretty well worked out now.

 

kdrolt:

Stock 305 heads, 1.84"/1.50"
187 iron LO3 head: 165 intake; 140 exh (Fast355)
081 iron LG4 head: 195 intake; 110 exh (ME Leigh)

I am researching these heads. Could you please elabortate on your source ie Fast355 and ME Leight. I have been ordering books from my library, searching the internet and contacting GM, which gives a lot of conflicting information. I could share some sources and the information I have found so far. Thanks

 

Hey 327_TPI_77_Maro
Tell me about your 327 with the HSR got any track times or dyno results? What cam are you using? Have you raced anybody on it?

 

I have run the HSR'd 327 at the strip. However, this was with a setup that, unbeknownst to me, only had 8:1 compression -- I have since changed to 58cc closed chamber heads. I was running 14.40s-60s at 97.5-98.5 mph with the super low compression setup, with really really bad 60 foots (over rich PE was causing a huge bog down low, I have since remedied this). I should be running mid-high 13s pretty easily in current tune. The engine is a 1967, so obviously no roller setup. I have an unknown grind Crane cam -- its quite large, it has a very choppy idle and makes max hp shifting around 6200.

 

WOW your setup sounds a lot like mine! I to have a hyd tappet cam its a single pattern its 292 dur .480 lift. I also got 1.6 rockers which makes it .512 lift. When I bought the engine the builder said it was 9.6.1 comprssion but when I did some research on my cylinder heads I found that they were 76 chamber so with Flat tops it had to be 8 something.


Then I bought some trick flows 64 chamber so I should be at 9.6.1 now. I just started it a few days ago and the idol is real choppy I love that sound. I might be upgrading the engine to a 383 some day so I went ahead and got a 58 TB and 30lbs injectors it seems to run real well with them. I got a built 700R4 with a 2600 stall convertor but I haven't decided on what gearing I want on the street 3.73 or 3.42. I'm just trying to get a idea of what my car will be capable of when I get it on the road.
What gearing are you using and how does it ride? Do you feel a real difference in power with the 305 heads?

 

I'm running 3.73 gears. Since I cruise at 75 mph, and have a Muncie 4 sp. w/ 1:1 4th, this gets annoying really really fast. My summer project is going to be to retrofit a world class T-5 so I can take this car up to really high speeds without putting excessive wear on the motor. Having the 305 heads bumping compression way up seems to be helping performance -- can't say for sure until I hit the track. The car does run excellent currently though.

 

The URLs for each of those, plus others head flow numbers, are found in a TBI thread called something like garage ported 193 casting. Do a search using those words, and when you find the thread (which is long) scroll down about 2/3rds of the way and you'll find my post that has the URLs as clickable links. EDIT: see this thread.

What's missing from that post is that no one has yet to port the 187 heads and flow them. BUT the 187s heads are very similar to the 193 heads with the exception that the intake valve is 1.84" diam on the 187 and the 193 head has a 1.94" diam intake valve. So IMO the 193 casting results, along with the results of the other two GM swirl port heads I listed show they can be made to work quite well, and probably as well as the 081s (i.e. nearly as good on the intake side and much better on the exhaust side). HTH.