NOT A CAM QUESTION, Valve spring question
 

I am looking to put a Comp Cam 01-775-8 ( Comps 731 clone) cam into a Merc Performance Gen VI 502 415 HP version. The rocker studs have been swapped out for adjustable and Comp Extreme rollers installed.
Here is the question I get varying answers to.
I am looking at these springs both Comp 924-16 and/or 26120-16. Can these be installed in the stock heads without removing the heads, or more simply put without machining?
I am open to other brand springs also.
I know there is brain trust on this site that has a definitive answer. Please provide solid experience responses.
Thank you in advance.

IMO, the springs you listed are too light on pressures.
The 731 is comparable to a 500efi cam and one of the main replacements springs used is the Comp 929's.

Thanks Griff. The springs I listed are the ones that Comp recommended.
Do you have any knowledge if the 929's work without any machine work to the heads?

you're going to change the springs and not set the installed height ? What is the recommend closed and open pressure for the new cam,

Not 100% but I don't think any machining is needed.

How many hours on the engine? What is your goal?? Doing just the cam and ECM tune will probably only gain about 25hp/2mph.
Are you going to do the cam swap in the boat? I did a complete top end in my old Baja.......Never again.
Way easier to pull the engine and if the engine is out, just pull the heads, have them checked and springs installed and then new head gaskets.

I would pull heads, check seats, do a valve job, check guide wear, and make sure installed height is right, installed height can be done in boat also as thats what sets pressure, but i would pull heads..

OK some additional info.
This is a carb 502 with just over 200 hours on the meter, it has been treated very nice, not abused and flogged.
My goal is 5,400 rpm and primary usage is just cruising around with infrequent visits to the 5200-5400 area. Some occasional sustained 4000-4200 runs. Boat is Formula 242 SS (1987).
Additional oil cooling has been added and I am running Stainless Gen II exhaust w/air gap intake. Motor is out of the boat but out of town, I will be traveling to put my accessories on, tune and haul home for install in boat. Not building an all out ball buster motor.
I am aware this is not the most ideal way to do the cam but it is all I can afford with the motor. Hence my question.
Griff, You say you don't think any machining is required, but, with which springs. I am also curious that Comp recommends the 924 springs or the Beehive equivalent and some think that is insufficient, not doubting your experiences but just confused.
I want to replace the springs and the cam would be great at the same time if it is financially feasible. A complete valve job is not in the plan.
Thanks for the replies and advice.

are these heads 088 ?

Isky 8005sp springs. I have a lightly used set if your interested.

If the 731 cam is close to the 500 EFI specs take a look at the Isky 8005A springs, I'm building a pair of 500's and am using these springs

https://www.summitracing.com/parts/isk-8005-a/

F-2 Most important is will they work with my heads/valves without any machining. Also, Griff thought the Comp 924's were not strong enough at 437#/in, same as the 929 he recommended?
the Isky 8005 is advertised @ 400#/in. I'm not a valve guy but I am getting a headache.

if the outside diameter is the same you should be fine, I think most of the OE type springs will interchange, I'm just stating what I'm running

[QUOTE=GLENAMY 242SS;4714031]F-2 Most important is will they work with my heads/valves without any machining. Also, Griff thought the Comp 924's were not strong enough at 437#/in, same as the 929 he recommended?
the Isky 8005 is advertised @ 400#/in. I'm not a valve guy but I am getting a headache.[/QU
I didnt bother to look up the ID of the springs you mentioned but I will add this, if your motor started as a 502 mpi, dont be surprised if you need to machine the top of the valve guides for different valve seals to clear the id of the new springs, I always seem to have to, Smitty

I see, the Comp's have a smaller I/D and O/D than the Isky 8005A. Guess I need to find the OD of the heads.
The motor was purchased a long block, anybody able to confirm 188 or 088 heads from picture or s/n?
Thank you Smitty

Comp 929 o/d = 1.535 I/d = .755 437#/in
Comp 924 o/d = 1.509 I/d = .697 347#/in
Isky 8005a o/d 1.530 I/d = .730 400#/in

Also make sure your retainers are compatible with the new spring.

First thing you need to do, is figure out what spring will fit. You need to measure the diameter of the spring pocket. Then measure the installed height. Spring pressures mean nothing , unless you know the install height. Lets look at the 8005A isky for example. IF installed at 1.900, it will be 125lbs closed, 365 open, and .140 from coil bind with that comp cams cam you listed (not close to a 731 crane or 500EFI cam btw). Now, lets say the installed height is 1.850. Now you have 145 closed, 385lbs open, and .090 from coil bind.

The spring must fit the spring pocket, and if its substantially smaller in diameter than the pocket, youll need to use either a spring locator, or spring cup. Then, you will want to make sure the spring fits the retainer, or buy the proper retainer for that spring. Bottom line, is measure everything. Once you have the dimensions, THEN you look at what springs will work.

Mild, you are correct, with the engine 700 miles away it is impossible for me to guess what parts are required and the extent of the work required not to mention I do not have the tools and knowledge to do this correctly!
I have made the decision to have the engine taken to a very reputable speed shop locally and have them do the ordering and installation of both the springs and the cam install. They also told me the 924 springs would not work and were way too soft for that cam.
What are your thought on this cam as compared to the comp 731. Thank you all for sharing your knowledge.

^^^ now you`re making some good sense
Thanx Trump!