Progress Thread H/C Swap Problems/Ideas


Active Member
Feb 6, 2020
North Carolina
Hello everyone, been a little bit since I last posted. I’m currently in the middle of swapping my GT40Ps to AFR 165 and my TFS 1 cam to a custom cam from Ed Curtis. Also have my lower explore intake on the way to Tmoss/ Matt Moss for porting.

The point of this thread is to document things I’m not so sure about and to seek advice as you all have helped me out before in ways in which I would’ve been completely stuck if not for your alls help.

If you all have seen my previous posts about my engine shake and about how I ended up resolving it with a new flywheel/clutch combo, unfortunately that only lasted for a whopping 15-20 minutes.

The shake came back worse than ever. I wish I would’ve gotten it on video but the entire engine was violently shaking side to side. The thin metal door panels were physically wobbling and the steering wheel was also shaking as a result. If the doors were left open at idle they would physically shake as well partly due to worn bushings but it’s still abnormally bad. Oddly enough driving wasn’t bad and the car drove pretty smooth at highway speeds. As soon as I had the final parts of the exhaust built I parked the car out of fear of it blowing itself apart and started the teardown. I’ve been building up parts for the last 6 months or so anyway so I figured it was time.

Aside from the shaking there were a few other things of note, I heard a light tapping sound coming from the drivers side top end which had been going on for a while but I just chalked it up to the roller rockers being noisy. Upon tear down however all the roller rockers looked great and none were loose. I should also mention that I followed the scorpion RR instructions to a T and shimmed all rockers individually so that they met spec. I also used thicker wall hardened Trickflow 6.350 pushrods as that’s what measured out to work the best. When inside the car and idling or free revving, a ticking could be heard from the drivers side of the engine that almost resembles loose rockers or first start of the car before lifters are pumped up. Never went away and seemed to be in sync with RPM.

After pulling the heads I didn’t find anything that jumped out other than cylinder #2 has a nice score down the middle of it closest to the exhaust side going down about halfway between the pistons TDC and BDC. The tops of the cylinder walls seem really smooth which is something I’d expect for an older higher mileage block like mine which I believe to be original to the car.

Things started getting iffy when I pulled the lifters however. I’ll get pictures of them tomorrow but there’s wear on almost all of the lifters that I’m not sure is normal especially considering my top end has been together for a little under a year and probably only 1k miles. I didn't prime the engine like I should’ve but I did have assembly lube on everything before startup when I put the top end together. There was also one lifter which I’ll confirm which cylinder and if it was intake or exhaust but it had what looks like a spot that had been damaged on the roller and either corrosion or varnish had taken place.

Upon pulling the cam I noticed that the lobe that carried the damaged lifter also has an almost identical mark. I’ll also get a picture of that tomorrow. Other than that though the cam actually looks pretty good to my untrained and very inexperienced eye.

My dilemma starts right here. I’m not sure if I should continue to put my brand new expensive parts back into this block which I have no clue of the condition of rod/main bearing conditions. I also don’t have any real way to check right now either as my shop build has been delayed indefinitely unfortunately and I don’t have anywhere to store an engine or at least very easily to tear it down.

I’m not sure if I should just pick up a good short block from someone and then continue the rebuild or if I should put the whole project on hold and have a block sent to a machine shop and then gone over throughly and maybe even a potential stroker build. Budget isn’t necessarily the issue it’s mainly time for me since I don’t have a shop it’s very difficult to leave an engine torn apart as it would be in the elements in my yard.

Here are a few pictures that I did manage to take with my disgusting oily hands and I’ll take more tomorrow. Let me know what you all think of the pictures displayed and I’m open to any advice/criticism on my poor engine building skills lol.






The cam bearing pictured doesn’t have any grooves or nicks in it or at least none that can be felt with a fingernail. I wiped the bearing off with just a dry paper towel before the picture. I’m not sure exactly how to tell if the cam bearings are worn or not. Also the heads seem to have random cleaner exhaust valves on some cylinders while the rest look normal.
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My take on it is if you have the funds and have contemplated a stroker short block then build or buy one now. Too many unknowns for me to even make a recommendation on the existing short block.

Be sure to contact Ed Curtis and ask him how the cam and heads will work with a 331 or 347. That may dictate more than anything.
My take on it is if you have the funds and have contemplated a stroker short block then build or buy one now. Too many unknowns for me to even make a recommendation on the existing short block.

Be sure to contact Ed Curtis and ask him how the cam and heads will work with a 331 or 347. That may dictate more than anything.
I’m with you on that one. I wish I knew more of its current condition. All I know is that the oil pressure is okay when cold but gets pretty low when warm. It’s also pretty nasty in the lifter valley. I’d rather just play it safe and not slap my expensive stuff into this block which may have something funky going on in the bottom end anyway.

I’ll be sure to hit up Ed sometime this week as that’s a good point. If they won’t play nice then I’ll probably just pick up a cheap block that’s in better shape than mine and have it refreshed and swap them out. I have a few timing cover bolt holes that are one seized bolt away from becoming just empty holes with no threads. One of them is already oblong and is missing the top half of its threads lol.
Also, white on the exhaust valves is oil burning. This could be from blow by on that cylinder i.e. worn out rings or it could be valve guides/seals.

If the GT40's are in good shape and you can find a known good short block for cheap than I would go that direction if you just wanted to get it back running and enjoy it while you put together a nice 331 of 347. I only say this as the fuel and induction systems will need to be thought out for the added inches and power so that can add to the time it takes to get all the needed parts around to make the swap.

Quick rundown of what I would look at for a stroker swap:
- The fuel system might need a larger fuel pump (155 lph or larger), larger injectors (so either a tune or MAF that is calibrated), and supporting things for these changes like fuel pump sock filter, new gasket for fuel pump hanger, injector o-rings (would think new ones would come with these but if you buy used and have cleaned). Those all depend on what you currently have in the car as they may be large enough to support the added cubes.

- The induction system could need a larger air filter (if needed), larger diameter pipe from filter to MAF and MAF to throttle body, larger MAF, possibly a larger throttle body, and I am not sure what upper and lower intake you are running but you will need to make sure they will support the air the added cubes will need. If it were me I would send the upper and lower to TMOSS and have him port them as it helped a lot with an old 306 I had with a Cobra upper and lower.

Anyhow, its obviously up to you as its your project but a running car is always more fun that one that isn't and planning a change vs being forced into one is always more pleasant.
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