The valve seals may be shot or the oil return holes in the ends of the heads may be plugged allowing oil to build up and run down the valve guides.
To replace valve seals on a Toyota Avalon, first, remove the valve covers and the necessary components to access the cylinder heads, such as the intake manifold and spark plugs. Use a valve spring compressor to remove the valve springs and retainers, then gently pull out the old valve seals and replace them with new ones. Reassemble the components in reverse order, ensuring all parts are torqued to the manufacturer's specifications. Finally, check for leaks and ensure everything is functioning properly before starting the engine.
You will need to have the heads for the 305 bored out to the same size as the 350. I disagree: you can use the 305 heads on the 350 block but you will increase compression as the 305 heads have a smaller combustion chamber. The critical dimension is valve clearance. If compression ratio is a critical consideration, different pistons may be available which will bring the combustion chamber back to size. the 305 is from the 3.671 inch bore family. The 350 is from the 4.00 inch bore family. All small block heads have the same bolt pattern.
if you get blue smoke only when you start it the valve seals are bad. if it blows blue all the time. the piston rings are bad.
You can not change A 305 to A 350, If you want A 350 you should buy one, You can use the heads on the 350, They are very likely GOOD castings, they will increase compression, This will improve the power of the motor, but it will be limitted because the 305 heads will not flow the volume of 350 heads, this means your Max RPM. will be lower than with 350 heads, its A give and take, If you get A 350 it will be A dirrect exchange with no mods. if you use the orriginal heads, and may be even if your 350 has good heads and they are drilled the same,The bolt pattern will be the same, no need to measure, just make sure ALL the holes are present, The harmonic ballancer is thinner on the 350 than on the 305, but the offset is the same to the front, so do not worry about the distance from block to front of ballancer, USE ALL THE BOLT ON PARTS FROM YOUR CAR, they will ALL fit the new motor,,,,,flywheel,starter,exhaust,tranny,pullies,brackets,fan,intake,carb,distributor,valve covers,,,,,, if you replace any of this, it may be hard to hook up everything. , Jamison.
it all depends on the head chamber volume of the 307 heads and the 350 heads that are being replaced. if the 307 heads have a smaller chamber volume then yes, they will bump up compression.
327 heads do not have the mounting holes like a 350. Alt, and a/c brackets although if you are not using serpetine pully's they have no problem going on a 350 I have a set on my 350 and it runs absolutely beautifully
To change the valve seals on a Mazda B2200, first, remove the valve cover and the rocker assembly. Then, use a valve spring compressor to carefully remove the springs and retainers, allowing access to the valve seals. Replace the old seals with new ones, ensuring they're seated properly, and reassemble by reversing the disassembly steps. Finally, reattach the valve cover and ensure all components are securely in place before starting the engine.
Yes, the bolt pattern is the same for all small blocks (as long as they're the same generation sbc). only thing to consider is your compression ratio. and if you're swapping the heads make sure your intake ports, exhaust ports and valve cover bolts are all the same.
1996 Trucks but not all, look for casting numbers 062 or 960 on the heads
all small Chevy heads are 65 ft lbsin a circular motion from the center out
No but they make plenty of Hemi heads for the Chevy and some even better. Hemispherical combustion chambers only benefit so much. I beleive the vortex has them. if you like the plug placement, enginers have been arguing about that for years, all just agree it needs to be exhaust valve.