3500 valves floating

[Superdave]

maybe the 2 sets of 915 springs i have are magic...





brand new 26915 spring sitting flat as can be on a stock seat from a '04 3500 head. It's a tight fit but i've never had a problem.

I'm still not understanding the benefit of using such a stout spring on a stock setup... the 915 as your recommending for him.

Might be overkill, the 986's would work fine as well as a few others that Comp offers. as far as LS6 Yellows i wouldn't touch them after seeing 2 break on a .506 lift cam. LS1's are decent but having to open up the LS1 shims and find 2.2L seals is a bit of extra work that i wouldn't want to do while swapping springs in the car.


the 915's/918's perform very well, the LSx and L67 guys use them all the time with great results.

[3400-95-Modified]

I look at the 986's as sort of in the middle of the two that you recommended, basing my numbers off of seat pressure. Granted the 915's and 918's are 313lb springs... and the 986's are only 280lb... But I also look at the 986's as something that's a little less stressful on a factory chain and such... He has a 100% factory engine, so I think a 313lb spring is not only overkill but could cause premature wear on a few parts, Hell with my duration lift and these springs, I'm curious to see what my chain looks like at the end of this year. I used a new 94 style one since my 04 one stretched badly on a Milzy LS6 spring combo in 15k miles. I also would not recommend the LS6 springs either, I ran them and I'm happy I got rid of them, those Toyota spring seats were not cheap!

Dave, measure the inside of that spring, I'm curious to see what the dia is... Comp says it should be .885 ID, and a 1.290 OD where the 986 is 1.00 ID and 1.412 OD

Also do you have a set of older 3400 valve seals to compare to the 3500 ones? did they possibly change size?

This is what the base of my 986's looke like going in on factory seals. Not the best pic... If I find a better one at home tonight I'll post it.

[Superdave]

The OD of the spring seat isn't consistent over the .22" tall surface, at the bottom it is .883 but at the top it's .890-.892. I suspect that's from the press at the factory. This is exactly why they snap into place yet work fine.

the 915 springs aren't perfectly round at the bottom but the ID measures .887 -.892. for the OD, it depends on where you take the measurements but 1.29 is in the range.

Tight fit but once the spring is snapped onto the seat you can spin the spring with minimal effort, in an engine coated in oil they'd have no problems.

[IsaacHayes]

OT: I still love that industrial grey paint Jon.

[3400-95-Modified]

OT: I still love that industrial grey paint Jon.

It is an awesome color when used properly...



Sort of On topic, those are the 986's all installed when I built mine