I'm wanting to get my facts right before ordering parts for my 350 rebuild. 350 ,.030 over, 416 casting heads, 700r4 trans with a c4 diff, not sure of the gearing yet. I've read that using these heads with .015 steel head gaskets will bump my C/R up to 11-1 +. Using .035 gaskets will lower it to around 10-1. Can someone give me more info if these numbers are right? The pistons are flat top with 4 valve reliefs and sit about .250 down from the deck. I'm wanting to run a summit 1103 cam and the rockers are stamped rollers. Not sure if the rockers are 1.5 or 1.6 ? Also if I bullnose the combustion chamber to match the 350 bore will I be able to run the .015 gaskets and still run pump gas, what's my best option ? This motor is going is a 31 tudor , looking to build a reliable runner. Thanks.
I would look for a different set of heads, something with at least a 64cc chamber . I'm pretty sure your pistons are not .250 down the bore
The pistons sit..., .250" down (in red above) from the block deck ? That's not only HUGE, but I've never seen correctly used Chevy parts with the piston deck, 1/4" from the block deck... Could you show us a picture ? Mike
Pretty common with many pistons nowadays , they depend on you decking the block . .025 down in the block + .016 gasket gives you .041 quench height , that's ideal . Shave the deck 010 use a ..026 multilayer head gasket ,you end up in the same place ., 041.
^^^ ya no way there 1/4" in the hole, more like .025". Bull nose the chambers? Stamped rollers? Hum Example: Bore: (diameter) 4.03 Stroke: 3.48 Cylinder Head Volume: 58 Effective Dome Volume: 4cc Deck Clearance: .025 Compressed Gasket Thickness: .035 Number of Cylinders:8 Compression Ratio : 10.77 : 1 Total Displacement (in.3) : 355.12 with .015 gasket Compression Ratio : 11.35 : 1 Ball park calculation, but ya, .58:1 difference in gaskets. 305 heads have small valves. A 64 cc head with 1.94 or a 2.02 intake would be a lot better.
https://nastyz28.com/threads/416-heads-on-a-350.45833/ Sounds like your read this thread ^^^^ Only other time I ever heard bullnose the chambers . I'd get some heads with bigger valves that flow better and run a better thicker more forgiving gasket and deck the block so it's new and straight and get the pistons down about .010" ( ten thousands of a inch) so the squish is about .045" Unless you like buying expensive gas for a engine with not much top end I'd look for a better combination. You should know what your rocker ratio is before going cam shopping.
This engine was rebuilt , has low miles just sat for a few years in the weather one cylinder had some water in it but piston was near the top. It cleaned up just fine , heads are in great shape, not looking to replace them, pistons look new and still has cross hatching in the cylinders, all bearings and surfaces look and mic good, just want a good running engine.
Yes I did read that plus many others. I understanding what he was meaning instead of just carving then out put a nice rounded edge out the the bore line.
Buy a 350 Roller Cam TPI engine and "ring and bearing it" then convert to carb and trash the serpentine belt system A roller cam is a better option with modern oils Do a good valve job , a decent honest cam, dual plane intake and 500-600 cfm carb The later model engines have 1 piece rear main seal that doesn't leak. You don't need roller rockers and high compression pistons etc.
I’m looking to build something cheap this engine came with this 31 project and is in good shape, all I need to is new rings and bearings, gaskets and seals and it’s done. I do have a tpi engine with a fresh lower end but no heads. I want to save that for a roadster build. I just want to be able to have something I can put 400 miles on in a day.
Don't go too high in compression, if you want a responsive daily driver. Cams and Compression are perfect bed partners. To get a responsive daily driver you want a short duration cam with minimal overlap in the timing. [this causes cylinder pressure to climb] If you go too high compression, a longer duration cam can bleed off cylinder pressure, but the engine will be weak down low [305 heads are not what you need for a temperamental high RPM engine] Just find some stock smogger "wheel chock" heads and give them a good 3-angle valve job. Get a machinist to measure you short block while still ***embled, so he can deck the block so the pistons are 5 thou above the deck, and use 0.040" Felpro gaskets. Use "drop-in" Z28 valve springs and a short duration 204° @ 0.050" x 0.428" lift Elgin #E1787P Cam and lifters. [This cam will pull like a diesel engine in the 1200-4200 RPM range] Top it off with a dual plane intake [I prefer the Holley Street Dominator which is an exact replica of the OEM Z28 intake ,that is cast in the same foundry] And a 500 CFM Edelbrock or Quadrajet carb This should net you 20 mpg and be really user friendly in traffic [especially with your choice of transmission and rear-end] Note: The reason I suggest decking the block ,is less meat needs to be removed [30thou on the block is equivalent cc reduction to 50thou on the heads, so the shouldn't be any intake misalignment] here is the Elgin #E1787P Cam card https://www.northernautoparts.com/part/ei-cl1787pk EDIT: If you already have the 305 heads, DON'T deck the block, just do a 3-angle valve job and de-shroud the valves with a dremel Then use Cometic 0.060 Head Gaskets [this will net 10:1 compression] 305 heads are really responsive in low rpm range driving.
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