98 Vortec 350 - comp ratio

[Diptenkrom]

definitely would double check but they list as self aligning. chart below says they are.

 

[df2x4]

For what it's worth you can get a set of US made Scorpion 1.6 aluminum roller rockers for around $270. I run Scorpion 1.5s in my Monte Carlo and they're great.

https://www.summitracing.com/parts/scc-scp1002/

 

[L31MaxExpress]

definitely would double check but they list as self aligning. chart below says they are.

Looked at the picture and didn't look to be.

 

[Christian Steffen]

huge HP supercars of today are using that wasted enegy to cook off smog. lol and they are the most efficient engines ever produced for daily drivers. i doubt in my lifetime i would see cold exhaust on a running automobile engine, but i would love for it to happen. maybe when they get 100% ethanol figured out. or if we could make a deal with china for some of the rare earth magnets.?

There is a balance to everything.. some combinations adding high octane fuel for extra timing won't do ****. Others it can make a huge difference. For example my 2014 Silverado loves e85 for the high octne, even gm reports a power increase for the l83 on e85. This is from the timing they add based on the alcohol percentage. Again, each combination is different, but less timing with lower octane does not always mean more power.

 

[Redneckgeriatric]

There is a balance to everything.. some combinations adding high octane fuel for extra timing won't do ****. Others it can make a huge difference. For example my 2014 Silverado loves e85 for the high octne, even gm reports a power increase for the l83 on e85. This is from the timing they add based on the alcohol percentage. Again, each combination is different, but less timing with lower octane does not always mean more power.

yep , big octane is needed for e85. or some super strong ring lands lol. more timing with lower octane means more power, octane is added to stifle the explosion. so it becomes high octane from necessity, not to make power. less timing and lower octane can and will (at times) make more power than high octane and TOO MUCH timing. there is a reason detonation is monitored and controlled. ionic sensing is arguably better than the antiquated knock sensor, but rednecks tend to use "other than neccessary " spark plugs and wires and coils. so, gotta get used to knock sensors pulling timing. its a balance.

 

[CW73]

definitely would double check but they list as self aligning. chart below says they are.

I had to drill heads for push rod holes with 1.6 rockers and they're still pretty close.. The Jegs rockers look pretty good if they are self aligning.

 

[Diptenkrom]

I had to drill heads for push rod holes with 1.6 rockers and they're still pretty close.. The Jegs rockers look pretty good if they are self aligning.

Yeah, i anticipate getting the holes done at the machine shop when i get the rest of the head work done. hopefully they wont think that is a reason to charge another $100 or something stupid. I will contact them to make sure on the self aligning point.

 

[CW73]

Yeah, i anticipate getting the holes done at the machine shop when i get the rest of the head work done. hopefully they wont think that is a reason to charge another $100 or something stupid. I will contact them to make sure on the self aligning point.

Right.. machine shops around here have gotten expensive. I drill them with a drill press and a new quality drill bit. I machine down the guides with the Comp Cams tool and a hand drill.

 

[Hipster]

by math i found on another forum and extrapolation it looks like the .030 MLS Cometic would put me just under 10:1 or so. i like that number, and i think it would wake her up a bit. but i dont want to HAVE to run 93+ octane in the 42gal tank, lol

which means skip the decking and just have the thing checkd for cracks/true and slap it back together?

You're assuming the published compression ratios are accurate. This is not true so your calculations from that number are not going to be accurate either. Never, have I ever measured a tear down that was even close to advertised numbers. Ford, Chevy, or Mopar. The only way for certain to calculate compression is to measure what you have or are building. If you want to run on the ragged edge of detonation one mis-step and you've built a detonation prone ticking time bomb.

Most published numbers come from a specially handled engine not your average run of the mill production line engine that's can be prone to tolerance stack up, built on worn tooling, core shift, etc.

Measure everything. You don't always hear detonation and when you do the damage may have already started.

 

[Redneckgeriatric]

a glass plate with a hole in center and a burret (sp) are your friends!