What does this look like? First picture I’m assuming is from rings or something and second looks like pitting no? What could I do about this I’m trying to avoid a machine shop. It didn’t have any issues before tear down. 3rd is different cylinder with similarity that may be putting.

Hello everyone,

General question for you all. I have a 68 firebird with an (assumed to be) original 350 in doing 224whp and 300wtq. Like all good pontiac owners I would like to put a 400 in it.

My question is this. Many people say the pontiac engines are expensive rebuild. A few have told me they're incredibly expensive to build.

Why? Is it just relative to a sbc 350?

Thank you.

First time doing this so looking for some opinions.

My honda atv jumped timing and woudlnt run. I pulled the head to verify that the vavles didnt contact the piston and bend. Also wanted to check if they are seated properly.

Going to need a new timing chain for sure but i noticed where the cam shaft rides is pretty tore up.

Am i able to clean this up and put in new bearings or is this head shot? Also is the cam shaft good?

Playing around with a 302 that’s currently efi from a 97 explorer and dropping it in a 91 ranger. Swapping to carb because I live under a rock. Looking for a cam that doesn’t kill driveability but still gives a good sound (unga bunga) what are we running?

TLDR: which cam chops and doesn’t suck to drive with?

I’m Planning on using Belzona 1111 to repair these lower liner bores on a c15 I’m building . It appears there already was already a similar repair performed the last time this one was overhauled . Crazy thing is it was never mixing fluids
This engine has probably been overhauled 3 or 4 times .

I spent a good amount of time on the phone with a Belzona specialist today and they swear that it will work , I asked a few other guys that build a lot of cat engines and they told me it will work if I prep the surface properly and do a clean finish

What do we think? Can I get another run out of her?

This is not for a customer , this is an engine that runs in my fleet of 60 trucks .

A friend was having the water pump leaking slowly. I offered to help as I have done this twice with success. As he was driving to my home, he had engine failure. The left secondary chain is off. Examining the head, I see a crack in two of the sparkplug tubes.

Has anyone replaced the head with success? If so, did you get a head from a yard, refurbished, or buy new? Is it worth it? It doesn't look as if the pistons are damaged, using a camera.

Thanks.

I just picked up a complete 307 olds v8 today and id like some advice on what i can do to it. I know that the windowed main webs are a massive setback if I want to make power out of the motor but id like to know if anyone has build a 307 for the street. I dont need crazy numbers, i plan to put this in a 1999 jeep cherokee XJ to replace the 4.0 inline 6 thats in it id ideally like to make somewhere around 300hp 320ftlb of torque. I think this is a fairly safe power goal for this motor and im hoping someone out there has built a 307 oldsmobile before and can give me some advice. If it helps the heads are 7A heads and I plan to swap them for better flowing heads

Hi everyone, I’m looking for some advice on head gasket sizing for my Subaru EJ207 build.
My engine is being rebuilt with a TOMEI EJ22 stroker kit, which uses a 92.5mm bore.
The current head gasket is a Cometic C4261-040, with a 93mm gasket bore and a thickness of 0.040” (approximately 1.016mm).
However, according to TOMEI’s EJ22 stroker kit specifications, the recommended gasket bore is 93.5mm.
Here’s my concern:
Cylinder bore: 92.5mm
Current gasket bore: 93mm
Bore diameter difference: 0.5mm
Radial clearance on each side, assuming everything is perfectly centered: 0.25mm
With a 93.5mm gasket, the diameter difference would be 1.0mm, giving 0.5mm of radial clearance on each side.
I’m concerned that the 93mm gasket may leave too little clearance around the cylinder bore, especially under high boost, high temperatures, and sustained high-RPM operation.
I understand that the gasket is clamped between the cylinder head and block, and that gasket bore size alone doesn’t determine sealing reliability. However, I want to make sure the gasket’s inner edge and sealing structure are appropriate for this particular setup.
My questions are:
Has anyone run a 93mm head gasket on a 92.5mm bore EJ20/EJ207 without issues over the long term?
Is a 0.25mm radial clearance generally acceptable for this type of engine, or is a 93.5mm gasket the safer choice?
Has anyone experienced head gasket failure, bore-edge damage, or sealing problems caused by an undersized gasket bore?
Would a Cometic 93.5mm gasket or a suitable TOMEI 93.5mm gasket be a better choice for this build?
I’ve had a head gasket leak on a previous engine, so I’m trying to be particularly careful with this rebuild. The engine has not been assembled yet, so I still have the opportunity to change the gasket if necessary.
I’m not trying to second-guess my engine builder without reason. I’d just like to understand the engineering considerations and hear from people with direct experience running similar setups.
Any advice or firsthand experience would be greatly appreciated. Thanks!

Just got my cylinder heads back from the machine shop. They did a valve job, resurface, and installed new comp cams beehive springs for me. Checked valve recession and everything is within spec. Removed a couple springs to check install height and they’re shorter than what I asked for. They’re not all the same height. (Some installed at 1.766 and others at 1.833) But I specified that the install hight was 1.9” (148in/lbs). I’m very annoyed because I wrote down 1.9” for them and they called to confirm + get the spring pressure rating.

So before I call them and bring the heads back AGAIN… is it possible that the heights vary because all the springs are set to the correct pressure and that required various hight difference for each spring? Could they have measured pressure with the springs assembled on the heads?

I’m new to building modified engines so I want to make sure everything is done right and I don’t have any issues. I’d like this engine to be both powerful and reliable. I’m intentionally leaving out what the engine is because usually when I tell people that work at performance shops/machine shops they tell me they have no experience with that particular engine and disregard any questions I have. Please let me know if they did a bad job or I’m just a newbie and don’t know everything (which I definitely don’t).