84TAProject

I was wondering if I am having valve float. When I first swapped motor, I had no problem barely being able to shift it in time to overrev 2nd and 1st. Now I can easily hit 3rd gear at 5300 rpm or so (of course the tranny slips, thats another story and a whole wad of cash). I thought I was just getting used to it and was quicker.

The other day, I get behind my father on the way to cruise night, and he decides to be immature and stomp on it. So me being the way I am rear the shifter back to 1 at like 15, and stomp on it, and low and behold pull on him. I hear him chirp 2nd, I hit 2nd at like 5400 rpm, and am catching up. At around 68 mph he pulls away, and at that speed Im turning like 5000 rpm. My cam (XE262, 218/224 @ .050) makes max power at 5300 rpm, and he just left me around then. I coulda swore I remember the first few times I spun the motor it floored me in the seat bad at that speed. If anything I should closed right in on my father at that rpm, as my max power is made there. The motor doesnt like to rev above 5000 in 2nd gear, and my heads arent all that bad except they need new valve seals. They are 76ccc 487 casting heads and they have big ports. I dont think its a breathing problem. My manifold is only rated to 4800 rpm and a book I have says that power can drop off bad above that rpm with that manifold, but I swore when I first installed the motor it spun right up.

Motor is from 1971, and has 105,000 miles. Do I need new valve springs? Are they really hard to put in (give me an excuse to pull the heads, I want to port them and put bigger valves in.)? Should I bother on those heads, I am planning on a blower soon so I wish to keep my pitiful 8.5:1 compression.

AlkyIROC

It's possible you need new springs. What springs are on the engine now? If they're original 1971 springs then they needed changing 15 years ago. That cam needs 981 springs. They have 110# of seat pressure. Stock factory springs are only around 80# and old weak springs you can probably open the valves by hand.

Change the springs, seals and if you decide to pull the heads, do some port work. I wouldn't put too much work into those 30 year old heads. If the don't already have screw-in studs then the cost to upgrade the heads will be more than buying some World heads.

If you have to upgrade the heads completely then consider these costs.

Machine the stud bosses down for screw-in studs.
Machine the spring pockets for larger springs (not needed for that small cam).
New valve retainers and keepers.
New valve seals. Positive lock seals are better but the valve guides need to be machined to use them.
The valve guides are probably worn out and need to be replaced.
Hardened exhaust valve seats.
Larger valves plus a 3 angle valve job.

Add to that more labor of:
Flat mill the head to make sure it's square.
Hot tank and clean.

Once you add up all the parts and labor to redo those old heads you could buy some new ones that out of the box will have all that work done already plus will have better castings for less than what you would spend on the old heads.

Just something to consider before you start spending money.