Engine Valve Spring Question

Ok so here's my dilemma. I had a set of aluminum heads (freebies) for my motor. They were from a buddy who was doing a TR6 and sold the project. Now that I'm doing the motor I have realized that the heads have been milled alot and the intake valve is sitting just up from the deck. Too much for my liking and my budget doesn't permit new aluminum heads at the moment.

So I'm going to use the stock E7TE heads until I can afford the upgrade. The cam I am installing is the Comp Cam 281HR (35-440-8). I'm thinking the stock springs may be a little weak for the cam so I was thinking about using the spring of my aluminum heads which are heavier double springs but I have no idea what the specs on them is. I'm figuring the aluminum heads would have been used with a HP cam so it may be a good swap.

Anyone have any input on this? The diameter is the same but the spring off the aluminum heads is heavier and they are a little taller. Think it'll work??

horse sence said:

what you will have to check is the valve height from the spring seat to the spring retainer for both heads . i dont think it will work because the aluminum heads are probably set up for taller springs for higher lift cams than the cast heads

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I think you're right horsesense, thanks. The retainers on the aluminum heads are right at the top of the valve stems and the retainers on the stock heads sit approx 3/16" down the valve stem which makes that even worse.

Wonder if there are performance springs for stock heads??

woodsnake said:

Is it your first build? (serious question, not trying to be snarky.)
Is your block already a roller block, or are you putting pieces together for the roller cam?
You can take both springs to your local machine shop, and they can give you some specs. Like what the coil bind is, and the actual spring rate.
A few things you need to be aware of here, are installed height, coil bind bind, and seat pressure.
I have had a very painful learning curve regarding cams, springs and push rod lengths. And I will take every opportunity to try and talk you out of an Edelbrock camshaft. All of the valvtrain measurements are CRITICAL measurements. Especially now that most engine oils do not have the required lubrication that our cars were designed to live with. I am in the middle of this retro cam kit in my 69 351W..
http://www.summitracing.com/parts/CCA-K35-424-8/
I still need to measure for pushrods, and I think it will be ready after that.

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Yes this is my first engine build so I'm a little overcautious about things which I think is probably a good thing.

The block is already a roller. It's a 1987 5.0HO. Was a low mileage block and there was no ridge at the top of the cylinders whatsoever. Factory crosshatching still visible. Block checked out really good at the machine shop and I am planning on using the factory forged pistons in the original bore. Bought a 400grit Flex-Hone to remove the glaze from the cylinders and will be using new Sealed Power Moly rings. I am converting it to carb from EFI though and am using the timing cover from a 289. Will plug old dipstick hole, use the 50oz balancer, front sump oil pan etc. It was a bummer about my aluminum heads being milled so much and I am tempted to buy a set of the $600 aluminum heads from e-bay (which seem to have great feedback) even though it was not in my budget. If my wife discovered that I'd be sleeping in the Mustang though so I'd better not at this time.
The cam I am using is a Comp Cam 281HR which has .512 lift. I had asked the guys at Comp Cam to recommend a good street cam for my set-up and this is what they recommended. I have seen this cam running in an otherwise stock Fox Body (YouTube) and it has just the right sound I want plus it generates good low end torque. The 281HR is done pulling by 5500rpm so I'm thinking a really nice fit. I think I am going to spring (no pun intended) for the matching Comp valve springs that work well with this cam in a stock set-up. Will check with Comp Tech first to get them right. Once all is installed I will use a solid lifter, set lash to zero and use a pushrod length checker to get the correct length.

Does this sound like I'm on the right path? I REALLY appreciate all your help folks. Much appreciated.