Just some information on Cams, rocker arms, and valve seal spacing from my personal experience with the problem.

Stock 360 cams have a .410 lift. Stock rocker arms are 1.6. So the stock travel of the valve is ( .410 X 1.6 = .656 inches).

Stock 360 cam with 1.7 rockers equals ( .410 X 1.7 = .697 inches)

My cam has a .490 lift and I run 1.6 rockers. ( .490 X 1.6 = .784 inches) or .128 over stock.

Recommended minimum clearance between the bottom of the valve spring retainer and the top of the valve seal is about .100 inch.

Therefore:
Uncompressed clearance ( stock cam - 1.6 rockers ) should be ( .656 + .100 = .756 inch)
Uncompressed clearance ( stock cam - 1.7 rockers ) should be ( .697 + .100 = .797 inch)
My heads ( .490 cam with 1.6 rockers ) should be ( .784 + .100 = .884 inch)
My original heads were not machined to allow the correct clearance for my cam/rocker arm setup so the valve spring keeper hit the valve seals. I ended up with a broken valve, broken rocker arms, and bent pushrods. Also ended up with two very ticked off people - me and my wife.

Stock heads with stock cam easily accomodates the 1.7 rockers. However, if you have a performance cam with larger lift be sure to check the clearances before installing the 1.7's or you'll end up with the same issue as me. If you want 1.7's and do not have the clearance you will need to pull the heads and discuss your needs with an engine machinist so he fully understands what you are doing and what you are asking. Basically he needs to cut down the valve guide enough to allow the seals to sit lower.

A second option might be to purchase valve spring retainers that have the landing low on the inside. Stock keepers have the landing in the middle. A lower landing raises the bottom of the keeper and if your flat valve spring retainer doesn't stick too far down you might retrieve enough clearance.

Hope this helps as I wish I had known about it before I put my engine in my truck.

Good luck.

 

You didnt mention what you have so I assumed it was a 2wd truck... yeah, a 52mm would be perfect.

 

Hi n welcome aboard.

K&N kit, 52mm tb would go well with the rt cam and m1
Get the B&G flash first, have it burnt for cam, m1 and 24s. Add the injectors after or same time as the flash.
Being a 4x4 1.7rr would help as well.

The MP *P5249549 is the RT cam. Specs are adv duro of 260/264 (probably around 206/208 @ 050) with .458/.467 lift (w/1.6) on a 109. Does this sound like what your buddy mentioned? NP running 1.7rr with that cam.

I ran the one bigger than the RT for 3yrs with 1.7 rr. The MP *P5007551 is the RT+10 cam. 272/278 (208/212?) with .467/.482 lift (w/1.6) Running 1.7rr it had .496/.512 total lift. I ran this cam with MP 600 springs/retainers and 7.0" pushrods (6.92 stock)with no issues. I would not go over .515 lift with a 1.7 rocker. (some say up to .525) Gearometry at high speeds gets dicey. Could slip off the side of the valve tip causing damage if you go higher.

 

I bet you're the kind of guy who would club baby harp seals

 

Turkeyhunter

Gross valve lift of .410" with 1.6 rocker ratio will only open the valves by .410"
Valve opening/lift is measured by multiplying cam lobe lift x rocker ratio used
MP cams do not supply the cam lobe lift #s but do supply gross lift with 1.6 rocker
Lobe lift is found by dividing gross lift by 1.6

IE
.410 divided by 1.6 = .256" cam lobe lift. To find lift with a 1.7 rocker multiply new ratio times that #
.256" x 1.7 = .435" of gross lift. That is how much the valve travels/opens with a 1.7 rocker ratio

600 lift springs will bind or lock solid at .585" of lift so best to keep gross lift under .575" or you could break something
Pushrod length and valve lash need to be set correctly or damage can occur

 

Based on what my engine builder told me on the cam specs it's what I said. I can also understand what yours is saying. I did not physically see what the cam looked like, but when the clearance was measured between the bottom of my valve spring retainer clips and the top of my oil seal, I only had .75 inches. The original plan after pulling off the heads was to machine the guides down another .200 t oget the clearance I needed. However, when we discovered the head that had the broken valve had cracked, I received two newly rebuilt heads.

 

Not to thread jack, but can I use the r/t cam in my 95 318 and would I see any gains?