SR code SF code 455's whats the Difference

That is news. As you know the parts books and an article, (maybe in the GS Xtra?), report from the factory only the following cam choices:

455 standard (non stage 1 cam)
455 stage 1 cam
455 HP cam (starting in 71 model year)
455 stage 2 cam

The parts 71 books, for what it is worth, also show only those 4 choices were all ever made by the factory.


Since we can eliminate the the bottom two, any cam difference would suggest a stage 1 cam would be the only choice if there was in fact any difference for a SF versus a SR. But I have never heard anyone suggest a factory stage 1 cam was found in 70 SR engines.o No:

 

Jim,
For you, I will add the info it shows for the 1970 455 cams.

Part # 1233232, MFG codes (RA-RB-RC-RD-RE-RF-RG-RH-RJ-RK) Markings; Gear machined on shaft, no groove
(This would be for Engine blocks stamped "SF" & "SG")

Part # 1382148, MFG codes (PA-PB-PC-PD) Markings; Gear machined on shaft, groove on #1 bearing
(This would be for Engine blocks stamped "SR")

Part # 1383853, Stage 1 MFG codes (PE-PF) Markings; Gear machined on shaft, groove on #1 bearing, groove between #1 bearing and lobe
(This would be for Engine blocks stamped "SS")


Now all this info is from the actual booklet the Buick Engineers carried in their pocket while doing Quality Control checks at Buick Engine Plant #36 in Flint, which is where all the engines were built.

This is not from a parts book, as in what parts were offered for sale as replacement parts, but supposedly lists the parts that were actually used during engine/vehicle production.

If you need more then this I can't help at this time.
Duane


PS. The 71 Engine book also lists 3 cam numbers. The 71 Stage 1 cam has the same part number as the 70 model, but the other two cams have different numbers then the 70 cams.

The 72 Engine book shows the Stage 1 cam as the same # and 1 other has the same number as 71, but the other is different.

So far that makes 6 different cams used on Buick 455's during 70-72 production, plus the Stage 2 cam.:laugh::laugh::laugh:


The big question here is does any of this really matter? When we rebuild the motors don't we always toss the old cams in the trash and buy new ones anyway?...........and the same with the fuel pumps?

 

Likely not Duane, but for the sake of the curious, thank you again!

I'll even thank you in Jim's stead.

Devon

 

Devon,
You're welcome.
Duane

 

The truth does matter here. This is why we are engaging in this little exercise. The over-arching issue is whether there is any performance difference between the SR and SF small valve 455 engines. This leads to the issue of the reason for the difference in horsepower ratings and differences, if any, in their respective components. Perhaps we can get Dennis Manner to speak to this issue.

 

Jim,
I remember Dennis talking about how the Stage 1 cams & BB transmissions were designed. During a resto session one of the guys said how our cars were killers from streetlight to streetlight and Dennis smiled and said they were set up that way. The parts were developed to get a relatively heavy car moving quickly out of the box, and keep it moving in the power range.

He also talked about how the 455s were designed for pulling power due to the number of owners that had boats & trailers.

I would imagine the "SR" motors were set up with more performance in mind, while the "SF" motors were set up for a heavier car plus pulling capacity. How this would relate to speed in a 1/4 or overall HP I can't say, but do know they were more concerned with keeping the motors in their power ranges, while at the same time keeping them reliable.


What surprises me is the amount of info I have on these cars. I guess after collecting this stuff for over 20 years you should have something. Someday I will finish digging thru my piles of info and know what I have. Of coures Mark Macoubrie has found more information about Brads GSX recently, so the search continues..................................
Duane

 

heres some info on the cams specs - but like Duane mentions - how many of you go faster guys still have untouched factory cams

 

Well it looks like those old worthless parts books yield the same results as what the guy who designed the 455 says is fact in this article. In the 70 model year there were 3 cams total. ( I am including the stage 2 cam)The ones in the SR and SF are the same and the engines are the same. And he confirms the outputs were the same but the horsepower rating numbers were artificially manipulated by the factory.

 

Yeah well the GM Factory book states there were 3 cams used at the factory in 1970 PLUS the Stage 2 cam that would have been an over the counter part.

You can believe what you want, however I do agree with your statement about "those old worthless parts books"
Duane

PS. If someone wants to take the time to do this they can look at the cams in both the 70 SF & SR motors and see if it matches the info as provided in the Factory book. Other then that you are making an assumption that the Factory book is incorrect.


PSS. Answer me this Jim, Why would Buick go through all the trouble to assign different part numbers and increase their inventory uselessly unless there was some type of difference in the parts.


This is just a continuation of the same argument we had regarding the Pliacell vs Spiral shocks.

 

Duane. Were the MFG codes marked on the camshaft anywhere? I just checked two cams removed from recently disassembled SF coded engines. Both were stamped 1233233 (I double checked this as it seems to be 1 number off) just ahead of the rear journal, and both have the groove in the forward bearing journal. I have a few more cams I can check if needed, one is absolutely from an SR coded 455. When I saw that the part numbers were different, frankly I stopped looking.

So, and I am a bit embarrassed by this, we don't all toss old cams out. ou: Not this pack rat anyway. And yes...I do have them tagged for which engine they were removed from. GAWD I need a new hobby !

 

Duane -- if I were you I would just go tell Dennis Manner he does not what he is talking about. After all, you have "all that information you have accumulated over 20 years" and he is just the powertrain engineer who designed the 455s.

---------- Post added at 03:22 PM ---------- Previous post was at 02:28 PM ----------

I am with you some non-performance related variations like:

The 70 Riv carb carried unique number and did not have a mechanical fuel pump;

The 70 SR 4 speed engine had a unique carb number and a z bar ball stud, etc

 

Jim Lore,
If you want to call Dennis to clear this up have at it, he is very easy to talk to, probably one of the nicest guys I ever met. He was certainly one of the Engineers that developed the 400 & 455 and was responsible for both the Stage 1 and especially the Stage 2 programs. (He built the Stage 2 parts during his lunch hours and pushed to get as many operable Stage 2 parts into the parts distribution network as possible.) I believe he also developed the Turbo charged Nailhead that was on display at the GSCA Nats years ago.

People here asked questions and I answered them with the factory info I have. It's that simple, so why are you trying to shoot the messenger?

This is not the first time factory info has conflicted itself, nor will it probably be the last. The logical way to approach this is to see what parts were actually used on the cars, like I did with the "shock question" years ago, or to give Dennis a call. You can ask him about the difference in Factory info. Maybe they changed things during the production years, all I know is whats written in the booklets.

I shared what I have and you can make your judgements from there, however there had to be some reason for the different coded blocks. Otherwise there would have been no need to have so many permutations for Buick to inventory.


Jim Jones,
"Were the MFG codes marked on the camshaft anywhere?"

I have no information other then what I posted out of the 70 book. For 70 it only listed grooves, or the lack of them, as identification for the cams. I think some of the other years called out paint stripes/dabs but would need to check on that.
Duane

PS. I am also a pack rat, just not with engine internals.

 

I feel the SR / SF differ in several ways ,water pump, dist set up for just a few. Remember these parts were put on the engine before it was painted.

Mark

 

To all,
I just got off the phone with Dennis Manner and he is sending me some info. He told me to check it over and see if I could figure it out. If I can't or have a question, he told me to send him some of my info so we can discuss this. Either way he said we will figure everything out.

He also gave me some pointers to locate differences between the motors, and talked about the "pocket books" the engineers carried around in the engine plant, which is the info I have.

So it will take a while but we will get an answer.

We also talked about the article on the Stage 2 4-bolt main motor/tunnel port heads I started years ago. I let him know I would start it back up soon so we could finish it this winter. He was up for proofing it.


Guys,
If you get info off 70-72 camshafts let me know, and if possible when the motors were built. It appears some changes may have taken place during the production year, so the date of the motors may be important.
Duane

 

In regards to Jim's cam(s) being one digit off.....I've seen that before on many GM parts. I've seen it on idler arms, vacuum modulators, trim parts, cast moldings...a LOT of parts that have either a part number or a casting number that's one digit off. It's the right part, I don't know why they did that. I agree with the other person about the details of the engines (dist., carb, fuel pump, water pump, etc. being the reason for the different codes. We know the dist, fuel pump, etc were on the engines because of the overspray. They weren't added later. We also know the timing curve and carb jets, rods and other internal parts can make a big difference in HP/torque figures on the same engine. Then there is the problem of those numbers being rear wheel horsepower, not dyno HP. And...we also know that GM deliberately underestimated some of those numbers. It's gonna' be a hard puzzle to solve now!

 

Frank,
I am not even going to try to figure out HP numbers or why/how much the numbers were changed. I am only interested in seeing what the parts differences were between your basic 455 blocks, such as the SR & SF blocks for the 1970 cars.

The water pump differences as well as the flywheel, z-bar ball, and thermostatic choke would be taken into consideration by the different manufacturing codes for each base block code, so some other factor is involved. I think the carbs are also taken care of with the stick vs automatic manufacture codes, but will have to check that.

I also need to disregard parts that were put on at final assembly like pulleys, power steering brackets/pumps etc, as these had no effect on the engine codes.
Duane

 

The two cams I checked were from fairly late 1970 engines. One block had a foundry date of D-18, the other had a date of E-14. I don't want to open the production # can of worms again, at least not on a public forum. If you need those, please request by PM.

I also have a low mileage 70 Stage 1 cam in a box in the basement. I can check it if needed.

 

Jim Jones,
I hear you and would prefer to gather the information privately and then see where it takes us. I see this research being collected the same way as what I put together for the 70-72 shocks.

With the shocks, the data collected disproved what I always assumed was correct, and was very surprising. Whether this will end up being that way or not we will find out.

Sometimes its easy to learn new things, while other times the data seems to drag you kicking and screaming all the way to the end. I have a feeling this one will be the latter.

Either way Dennis Manner is willing to open up his notes to help find the truth, and go along with us for the trip. You can't ask for more then that, and I am more then happy to work with him again.

I will get back to you, but probably not until tomorrow. I have an awful lot on my plate today.
Thanks again for your help.

Frank,
Thanks for the insight on the part numbers.
Duane

 

Sure...glad to help...you have helped me! It's definitely true about the parts numbers on the actual part being one digit off from what's on the box or listed in the book...it's very common, but not always. I have a lot of NOS stuff here, and I've seen it multiple times. I think pitman arms are like that, also, along with many other parts. It's the reason why many peeps have difficulty ID'ing parts, if the box and tag are gone on an NOS idler arm, the casting number is off by that digit and you can't find it in the books.

 

"if the box and tag are gone on an NOS idler arm, the casting number is off by that digit and you can't find it in the books."

Ah, I think we found another parts chaser here.:laugh:
Duane