Replacement camshaft for 427/435

[John Pelkofer Jr]

Hello, Can anyone give me input on Crane cams CRN-968561 replacement for the origional 1967 427/435hp cam. Does this cam's profile offer stable idle vacuum
to control vacuum advance and power brakes. The engine is in stock configuration and would like a cam that gives the stock idle and power of the origional cam. This car is shown and driven on weekends. If anyone has a better
cam of choice, please recommend it. I should also state that it is a side pipe
car and I would like to retain its origional sound. Thank you all in advance for any and all help. John

[Duke W.]

Re: Replacement camshaft for 427/435

I don't know if that camshaft is an exact reproduction of the OE SHP cam, but if it is their website should unequivocally state that it is such.

The F-M Speed Pro CS-165R IS an exact reproducution, but it has the rear journal grove that is required on earlier blocks. You may have to modify the rear bearing feed hole.

This issue was thoroughly vetted about a month ago. The search function is your friend.

Duke

[William V.]

Re: Replacement camshaft for 427/435

John

I installed the Crane Blueprint replacement cam for my 65 396-425. The grind is the same as stock origional. Good idle with a nice exhaust note and strong mid range. Someone please correct me if I'm in error but the 65-67 425 & 435 used the same cam. The 1/8" X 1/8" rear journal center located oiling grove is needed for the 65 & 66. however, a cam with the grove can be used in later engines without concerns.

BV

[Terry F.]

Re: Replacement camshaft for 427/435

a cam with the grove can be used in later engines without concerns.

I believe that is true only if you modify the bear. Terry

[Clem Z.]

Re: Replacement camshaft for 427/435

you will have a large internal oil leak around the rear cam bearing because the cam bearing has a large oil feed hole and the groove in the cam gives it a path for the oil to come out 360 degrees. without the groove the solid cam journal acts like as a restrictor limiting the oil flow which comes in at the bottom of the bearing.if you use the grooved cam in a 67 up BBC you must solder the original oil hole shut and drill a new .062(1/16")diameter oil feed hole

[Clem Z.]

F/M catalog lists the CS165R as a replacement

for GM# 3904362(3904366) which is the 67 up BBC solid lifter cam and should not have the grooved rear cam journal. i have not seen one of these cams for years so i am not sure.

[Steven C.]

Re: Replacement camshaft for 427/435

John, I own a 435 pipe car and discussed this very issue with Crane prior to a recent purchase. Their tech (Jerry) explained to me that the 968561, 560/580, is soggy on the low end and will need race gas to run a minimum 11.5:1 compression.

He recommended 134781, 567/590 as the RPM range is lower 34-70 and it is more streetable. I like it so far.

[John Pelkofer Jr]

Re: Replacement camshaft for 427/435

Thank all of you very much for your advice. I will talk with Crane cams tech department and feel I will follow Steves advice of the 134781. Again thank all of you, this forum always supplies valuable information. John

[Duke W.]

ICEBERG, right ahead!!!

You guys are headed for a disaster. I elected earlier in the day to disengage from this thread as I have grown weary of rearranging deck chairs on the Titanic, but I got a phone call this evening from a VERY KNOWLEDGEABLE L-71 owner (he has several) who I have been collaborating with on L-71 system engineering issues.

He is having password problems, so he asked me if I would paste an e-mail he would send me to this thread. I agreed, and the following is the text of his message.

"John I am not sure you will attain your goals if you choose crane cams #134781. My reasoning is that I ran crane cam #133841 which is a milder cam and it displayed lower vacuum and more cam lope than I wanted for that factory sound! In my opinion the crane catalog # 99193-01 is misleading. It makes 435hp owners at first think their replacement cam is #968561 when in reality that is a 430hp L88 cam. I honestly believe the correct factory replacement cam for a L71 435hp motor from crane cams is # 969961 and that is what I am now running without any problems."

John N. also told me that he has discussed this issue with Jerry Clay at Crain, but Jerry wouldn't budge, and I'm not surprised given my own conversations with Jerry.

John elected to install the Crane cam that he believes is the reproduction of the SHP cam in car #1`and then had both cars tested on a chassis dyno. The SHP reproduction in car #1 made GREATER TORQUE BANDWIDTH and MORE PEAK POWER than the high overlap Crane grind in car #2. He send me the dyno sheets.

Further, the L-88 cam was specifically designed for racing with headers and open exhaust for a power bandwidth from 5000 to 7000 and is probably one the the worst cams you could pick for a road engine.

The OE SHP cams, both the early grooved rear journal version and the later '67-up version without the groove use the same lobe on both sides. It has 242 deg. duration at .050" lifter rise above the base circle. The inlet lobe point of maximum lift is indexed at 108 deg. ATDC, and the exhaust POML is 120 deg. BTDC, for a LSA of 114 deg. Gross lobe lift - straight off the GM drawing - is 0.30572".

If the cam you buy does not have these specs, it is not an accurate reproduction of the OE SHP cam, and no other cam is likely to yield the combination of road friendly torque bandwidth and power that this cam will in addition to maintaining the OE idle characteristics.

Any "reproduction" camshaft MUST be manufactured to the dimensions and specifications of the original GM drawings, and it is not that hard to make at least some cursory lobe measurments to see if this is or is not the case. If even ONE measurement is NOT to the GM print, it is NOT a "reproduction" piece. A true reproduction camshaft is dimensionally indistinguishable from an original. Anything less is just a different camshaft design, which probably won't work as well.

Duke

[John Pelkofer Jr]

Re: ICEBERG, right ahead!!!

Hello Duke, Thank you and your friend for your input. I had a conversation with my local Chevrolet dealer and in the current performance catalog they offer a blueprinted reproduction of the origional cam, ironically made by Crane. I checked the specs and they are identical. When I purchased this car an engine builder already installed the latest L88 cam. To say this cam is not streetable is a gross understatement. Thank you for your valuable advice. I am going to install the blueprinted replacement. By the way, I am the man sitting on deck with you and would be glad to buy you a drink while the band plays and the ship goes down. John

[Duke W.]

Re: ICEBERG, right ahead!!!

I don't see such an animal in my '06 GMPP catalog. The only mechanical lifter cam and lifter kit shown is 12364058, which is clearly the L-88 cam, but they also refer to it as "435 HP", which is incorrect and will probably lull a lot of buyers into the iceberg.

What part number are you talking about?

Duke

[Clem Z.]

the "07" catalog has no mark IV

solid lifter cams listed. try F/M although some big GM parts houses may have some old stock left.the correct GM part # for the 143 cam and kit is 12364057. the cam had a GM part #3904362.

[John Pelkofer Jr]

Re: the "07" catalog has no mark IV

Thank you Duke and Clem, I called GM today and got the specs for the
12364058 cam and found them to be the same as the Crane L88 replacement. After reviewing the cams offered by GM, I purchased the Crane#969961. It is listed as the replacement for the 427/425 and 396/375 engines. This cam is definitely
a closer reproduction of the 427/435 cam profile. This cam kit is available
under part#12364057 as Clem stated. Again thank you all, my ship is headed for
calm water. John