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This guy did seem honest, I measured 2.07"/1.56" valves. I opened them up to find a cutter was used under the intake valve and the bowl was opened and the guides were machined for positive seals. I got my snap gauges and 0 to 1" micrometer, so I will measure guide clearance since I am not filling the cross overs on these heads, will work fine with my Performer intake. Here are some pics.
Another question, are new guides smooth inside? These have a pattern like a knurling was done, not smooth inside. Either way more work than I thought on these heads.
That looks typical to me. Nothing to be alarmed about.
As I understand knurling, it is an oil control and helps keep the guide lubricated while still maintaining tolerance. Some consider its a short cut but other wise can provide a good service life, and its been done for a long time.
Ask your self, what did you expect for 400 bucks? I'd run em.
That looks typical to me. Nothing to be alarmed about.
As I understand knurling, it is an oil control and helps keep the guide lubricated while still maintaining tolerance. Some consider its a short cut but other wise can provide a good service life, and its been done for a long time.
Ask your self, what did you expect for 400 bucks? I'd run em.
Less than this to be exact, I just wanted to see if the bowls were opened and that the center exhaust clearance was adequate. These heads will give me 9 to 1 compression is supposed to have upgraded springs. I guess I should try measuring installed height, planning stock rockers, bridges and under .500" lift.
I know but I may leave them as is, not a max effort build, I will be happy with 325 hp and 350 tq, stock 76 bottom end with a Cutlassefi custom cam. With a 2300 flash stall, 2004R, and a 3.90 posi to replace the 2.78 open should reach high 13's. The guy thought nothing was done to the bowls and the positive seals were unexpected as well.
You had the numbers rite, sounds like you have a good recipe going for a nice build. Its great to hear another SBO engine build will work out well.
Cheers
Eric
I know but I may leave them as is, not a max effort build, I will be happy with 325 hp and 350 tq, stock 76 bottom end with a Cutlassefi custom cam. With a 2300 flash stall, 2004R, and a 3.90 posi to replace the 2.78 open should reach high 13's. The guy thought nothing was done to the bowls and the positive seals were unexpected as well.
With a 2200 stall, 200-4R, 3.73 rear, with stock small valve #7 heads I went 13.02 @ 103mph with a 73 stock 350 bottom end in a car (78 Cutlass with power windows and seats) that weighed 3450lbs with me in it. That was with a Lunati 221/230 cam. Perfect street car with all the manners you would expect. 9:1 compression.
Take the time and blend the seats, the heads are off.
Also, your valve to guide clearances are subject to scrutiny. It takes a talent to distinguish the actual size of the guide with a ball gauge. I personally sucked at it for a lot of years. I was always on the high side of size.
Also, iron replacement guides usually have a knurl in them to begin with. Your heads definitely have iron replacement guides, and the knurl is normal. That can mess with your clearance numbers.
At the end of the day, you should check all clearances on every guide. Why? Because you can. It's good practice.
Thanks, they do look like replacements and would make sense with $1200 originally spent on them. I measured by the same guide a few times to get what felt right. What is the minimum clearance for iron replacement guides in the center exhaust guides? I will measure some more and may do some careful blending.
Thanks, they do look like replacements and would make sense with $1200 originally spent on them. I measured by the same guide a few times to get what felt right. What is the minimum clearance for iron replacement guides in the center exhaust guides? I will measure some more and may do some careful blending.
.0022"-.0025" is what I set them all at. A little tighter if bronze. If you are at .003" you will be ok, you'll just wear out the seats and guides quicker.
I will measure my #8 heads installed height and them measure another set of guides in the next few days. I may be off, as you said not easy to measure. I need to get the same tension on valve and snap gauge with the mic. I also need to get the snap gauge adjusted right in the guide. I have a set of Comp roller tips but they are loud in my aluminum valve covers plus I need conversion studs or tap to 3/8" and steal off my other heads.
Last edited by olds 307 and 403; December 23rd, 2016 at 10:36 AM.
What do you mean by " snap Gauges" ? Are they like telescopic gauges? if so they are difficult to use until you get good with them. Maybe the shop that did the heads for you have a set of Pin gauges for small diameter holes you are trying to get a measurement from.
I've been in the Tool & Die/ machining trade for over 30 years and still have a hard time with telescopic gauges haha, and they aren't a cheap set they are Starrett.
What do you mean by " snap Gauges" ? Are they like telescopic gauges? if so they are difficult to use until you get good with them. Maybe the shop that did the heads for you have a set of Pin gauges for small diameter holes you are trying to get a measurement from.
I've been in the Tool & Die/ machining trade for over 30 years and still have a hard time with telescopic gauges haha, and they aren't a cheap set they are Starrett.
Yes, the telescopic gauges. I agree, they are tough to read. I measured both heads valve heights, different. I think the gauge from Mondello is the way to go. I should try off the valve cover rail to valve top, I think spring pockets are too different between #6 and #8 heads, just thought of that. Makes sense, that is where the Mondello gauge measures from. I am hoping to be able use the non adjustable valve train, I hate adjusting valves. I will pull another valve set and see what I get, the measurement probably is tighter than what I am getting for a reading.
Last edited by olds 307 and 403; December 25th, 2016 at 07:26 AM.
Do you have a depth mic? That would give you bang on measurements in the spring pockets. You could put a steel rule over the valve cover rail, use a caliper as a depth mic and measure them just subtract the steel rule from the height.
I'm learning a little bit from measuring the heads I have to duplicate, I met a guy that owns Red Line racing up here who is helping me out with these heads. I hope to get more time in the new year to continue with my experimental heads.
Sounds like your doing an awesome job with your engine, I'm learning from you all here.
Cheers
Eric
No depth mic, as long as it is close enough to not bend push rods is my goal. I will be using composite head gaskets .011" thicker than the factory shim head gaskets.
With a 2200 stall, 200-4R, 3.73 rear, with stock small valve #7 heads I went 13.02 @ 103mph with a 73 stock 350 bottom end in a car (78 Cutlass with power windows and seats) that weighed 3450lbs with me in it. That was with a Lunati 221/230 cam. Perfect street car with all the manners you would expect. 9:1 compression.
Take the time and blend the seats, the heads are off.
Also, your valve to guide clearances are subject to scrutiny. It takes a talent to distinguish the actual size of the guide with a ball gauge. I personally sucked at it for a lot of years. I was always on the high side of size.
Also, iron replacement guides usually have a knurl in them to begin with. Your heads definitely have iron replacement guides, and the knurl is normal. That can mess with your clearance numbers.
At the end of the day, you should check all clearances on every guide. Why? Because you can. It's good practice.
Your 78 is 300 pounds lighter than my 88 Brougham, was 3780 with me in it and the stuff in the trunk. I plan on stripping the interior on my 88 before the 424 goes in, hoping for a few hundred pounds with only a single racing and no carpet. I am also thinking new rear control arms are necessary for a decent 60 ft. I will have to see how much the 70 weighs, hopefully less, the 2.78 open gear will kill me till I switch to a better gear, thinking 3.90 but that is a grand with the Type O in parts alone.
The installed height on the #8 head and #6 heads looks like just under 1.5" on both from the valve tops to the valve cover gasket surface. I should probably have the Mondollar tool to double check.
December 16th, 2016, 05:24 PM
