GM Camel Hump Heads (492) & Chevy 355 With TRW L2252A Pistons De-Tuning Queston

By the list of parts and modifications to that engine, you're looking at a lot of parts swapping to enable you to use basically the block, crank and rods. Most of the other parts are high compression, high HP pieces. If you're looking for a good engine for your C4, why not sell this one and buy what you need. Probably come out ahead.

 

How many ways can this horse be flogged ?

 

Looking at those solid mounts, an old accel dual point and the plugs screwed in all crooked I will give you $500.00 and get that out dated junk out of your way.

 

I could be wrong, but I think these angle plug 492 heads were over the counter only.

 

Very similar to what I ran in my sprint car back in the 70's. I never had a detonation problem. Oh wait; I did run alcohal. That does change things.

 

I did weight the numbers and I think it going to be way more expensive to rebuild the engine it the Corvette as it needs everything. Have you recently familiarized yourself with machine shop engine rebuilding services. In my area there's only two engine rebuilding shops that are still in business and with in a 200 mile radius. Just to service the block and crankshaft by only freshening everything up is I was quoted between $2,500 to $4,000, and somewhere in between for a basic build.

Obviously the higher end of the rebuild I quoted above is with the shop sourcing the internals, but not including the heads or camshaft.

I don't have a clue as to what this engine combination I have here in this 355 is actually worth, but I don't think anyone is going to come close to paying anything near the $2,500 for this engine.

I would rather swap out the cam and pistons and take my chances that I can get this into a suitable power plant for the Corvette.

 

Is your Corvette automatic or 4 speed, are you planning to keep crossfire fuel injection

 

What a shame to "detune" that engine... It has some really great parts and would be a blast in a light Hot Rod. Angle plug 492s big factory HP balancer , deep groove pulley. I'm sure it has a forged crank ,4 bolt mains and probably Pink rods... It was a serious contender in its day. I would buy a good used stock 350 for that car.

 

It originally had 4+3 manual transmission (which I still have and it's still in good working order) but I swapped in a BW T-10 that was rebuilt with upgraded internals.

No, I removed the CF injection right after I bought the car, and I put a Holley Sniper kit I got off Facebook market place.

 

I would really like to keep it just the way it is and use it for a track setup, but I'm in a dilemma as there's no more drag strips in my area, (the nearest one is now in Maryland and that's just too far of a ride for me) and E85 is only available at one filling station that's 85 miles away.

So I'm trying to come up with an alternative use for this engine, and I'm leaning towards a detune and swapping it into my vette.

I could sell the TRW pistons and camshaft for a few hundred dollars and put in the Kieth Black pistons that are brand new in the box. They are part of the stuff I inherited and I'm almost thinking that my relative might of had them on the shelf for this exact same reason. He was a big drag racer and loved going to the drag strip, but it seems that the days of going to the race track are in its death throws. I see more and more tracks are closing and being replaced with condos, and town homes.

 

You will find that hypereutectic pistons run a very tight piston to wall clearance compared to a forged piston. In my estimation the existing bore is too large to accommodate a hypereutectic piston.

 

On another note I wouldn't talk too much about the intended recipient of the engine because this forum is 1965 and earlier.

 

I would go with forged jugs, as I know they are designed to fit the cylinders with a much looser piston diameter, but I think the problem of a tighter cast or hypertectic piston could be negligible if the cylinders were given a light honing.

Of course that would require a more diligent watch and measuring with a bore gauge.

 

sorry--jugs (pots) are carbs and slugs are pistons...

 

Any speculation is pointless anyhow until you tear it down, it could all be worn out, it's already 60 over if I read correctly. One bad thing is the dip stick will now be on the wrong side and the manifolds may not fit those heads. I think the motor in the car has knock sensors and the list goes on. How about $600.00

 

Seeing the pictures of the heads, and everything else on this engine I personally would never change anything on it, or use it in the '84 Corvette! Someone built up a very good race engine, and I'd consider it blasphemy to change the way it currently sits.
I'd either rebuild the Corvette engine, or find a decent SBC 350 on Craigslist and drop that in the Vette. Most guys would love to have this engine for a strip car to enjoy as it was intended when built.

 

I completely agree. I have come across good SBC’s for almost nothing anymore since people are pulling them to put an LS in. I couldn’t pull that engine apart. Guessing it runs pretty dang good as is and would save it for a race car.

 

Get a good engine cradle , But not needed to start up on Floor , some knowledge needed though to do so.
Prime up oil pressure manually with oil primer , turn every 45 degs by hand
Making sure turning over 3-4 times .
Making sure oil out of all push rods to arm's .. reading on oil gauge , But I have done enough I can tell by the strain on the drill if oil pressure is good.

Are you sure R-Cam set up , Look to be
Single spring with damper , whats seat pressure,,
Is it Solid or Hyd , Does not look to have Lash caps , grab a few rocker's on close valve & see any play ,,,
Show us a plug , & number that was used , Buy pic seems thin intake gaskets, By looking @ distributor does not look like intakes been cut , intake does not look been cut, a feeler gauge will give a close read on Head gasket thickness , Pull distributor does it have a bronze gear. Slap a HEI in . Are original #s on pad removed.
1 wire start up bolt some stock Exhaust manifold on Start up , keep low on Rpms , Bolt a carb on ,
Since you donot know cam , on back barrels take .030 thou mechanic wire , slide in between blade & bore & tie off ,
This is to keep front blades not p*** transfer slot. bolt a fuel pump up , cheap $30 eletric or $15 mechanical,
One Gallon jug , hook up a Rad or fill block up with water , if no rad blockoff
Water pump inlet ,,, No fan or belts or Alt needed , bring up to temp , check heads with Tem gun ot mechanical gauge, check Oil pressure , for start up cheep oil 10/30 or straight 30 .
I would set timing before start up @
15-20 deg BTDC before Even attempting to start, bring piston up to timing mark
Power HEI turn distributor by Hand very slow you can hear spark or use light you will see when rotor & # "1"
Cross ..
After start up oil checks out ,, Then when cooling down to around
100-140 degs , Do a compression check & also Leak down ,,,
You can just for start up , 87-94 oct .

If this engine a true 11:5 there ways to run off 93,94 .
I run a blown with statice 11:1 under boost 13:5 with a Non lock out distributor & No octane adder ,
No Meth ,, theres just tricks to work around ,,,
Also if solid you can run looser /wider
Valve Lash ..

In vett find a 5.7 Vortec buy a $150 china intake , maybe cam change ,
Stock Vortec Heads are close or will out flow the Angle heads But Not Bowties

 

By the bore scope pics, I notice the honing on the cylinder wall, and to my eye, I don’t detect a ring groove.
Myself, I’d venture a guess that there’s not much use on the engine.
Maybe just pull the rotating ***embly, run a dished .030 piston, and have the ***embly balanced. I’d think you’d be in the 9-9.5 static CR, then change the cam.

 

Again your not going to swap from heavier forged pistons with out re balancing.
So a few hundred for the balance

Its also possable there floating wrist pins or even bushing in the rod ends you may nit want in your street engine.

You will likely run into proper piston clearance issues with new pistons and after all that your running on used cylinders .

Not going to get much for used high compression pistons or some unknown cam.

those are over the Chevy counter angle plug heads and were about the best when they were sold but that was at least 40 years ago .

So when you get down to basics you have a used over bored block , maybe a crank thats been balanced for forged pistons and some old performance heads that likely do not have hardened seats for unleaded gas that may or may not need work .

It sounds like you dont want to spend much so the easy thing to do is swap the heads for some later model 72cc open chamber heads and sell those . You might get $500 for the angle plug heads if there good.
Then your not tearing the entire engine apart.

You might be better off to try to get about $1500 out of what you have and putting that towards rebuilding a different engine or crate engine .

 

Totally agree on the speculation for the most part which certainly pertains to the camshaft, crankshaft, and connecting rods.

I do know what the pistons and heads are. Pistons are clearly stamped for 30 over-bore. And the heads are 492 angle plugs. I was in touch with some friends of my deceased relative and they told me that that he had that engine rebuilt sometime in the very early 90’s. They believe it has seen no more than 20 or 25 p***es at Englishtown NJ before it was pulled, and a 454 big block was swapped into his Chevelle race car.

The 84 vette is running a Holley Sniper on the stock 5.7L engine so replacing that engine with this one is not going to be much of an issue with exception to the exhaust manifolds, but I have the headers that were used on this engine.

lol…. on the $600 offer as that's too funny. I’m sure I could fire sale this 355 for twice that, but I want use it for the replacement engine in the 84.

 

I hear what you are saying, but buying a used 350 off Craigslist or Facebook marketplace is taking a chance on a lot of unknown things. And I had already ventured into that route Mandy years ago on a 2.3L Ford Lima engine for my SVO Mustang and it was not a good outcome. I ended up swapping in a 302 out of 1995 Mustang (easy swap) which was insurance totaled from a guy who only wanted $200 engine and $100 for the 5 speed transmission, but I had to pull it out.

 

Lots of good information you provided here. I do have some experience on priming a running an engine that has been idle for a long period of time.

I don’t have a pedestal style engine running stand, but I have run a few engines on a poor man’s two by four constructed stand with not much issues.

If you wouldn’t mind me asking, but what are some of the ways you mentioned about running a high compression on 94 pump gas.

I know about reducing the timing via spark advance, but that is just doing a distributor recurve modification and reading the spark plugs.

Would love to get more of your input on this as this engine swap for the 84 is not going to be a daily driver. Just more of a power ride to go out a few times a month and have some fun.

 

What’s your opinion on how far you think the piston is sitting below the deck. I don’t think it’s anywhere near a zero deck block or even if it was decked very much at all because I can still read the indentation stamping on the block.

Usually when the block is decked those indentation stamps get machine away.

With that in mind I think that this block might have a light machining to just level the deck.

I can post a picture of the stamped area if it would help things out.

 

I actually agree with you on venturing down the road of just swapping out the heads for a more suitable set that would leave the rotating ***embly intact and untouched with the exception of a camshaft swap.

I’m sure these 492 heads could fetch a good dollar from someone who is looking for some 64cc angle plug heads.

 

Look at the pad on the p***enger side of the block, in front of the head. If no stamping there, then it’s been decked, but still don’t know if zero or not.
Well, you can tell for sure if you’re pulling it apart, and I think you’d want to know your next steps to prep it for your intended use anyways.

 

@MoreHPplease
More likely this will be moved to off Topic ,,
The Sniper with Lap top needed to ACCESS more tunable then the hand held ,
With Ethanol fuel you can get away with more then straight Non ethanol gas. Sniper a plus then dealing tunning with carb , You definitely do not want
E 85 for a few reasons , Not all gas stations sell ,, Need big gas tank , let say you get
15 mpg on gas , E85 7 ish,
With carb & efi , Meth mix under WOT when needed can be added ,, Not like you are going to be @ WOT more then 95 % time on street

 

Here’s a couple pictures of the block with stampings.

 

I’m now thinking it would definitely make more sense to swap out the 64cc heads for something more usable on pump gas.

Do you guys have any opinions on what would be a more suitable set of heads that would work well with those TRW domed pistons.

The heads off the 84 350 engine are shot and most likely are warped and possibly cracked due to an overheating problem that left me stranded. I haven’t had the time to fully investigate that engine as I was in the middle of moving to a new house right after I parked the car. So it’s been sitting for almost two years now and I’m all settled in at my new house and ready to move along on that project.

 

Some pistons have enough meat to machine all or some of the dome, my buddy made a jig for his lath to do a set of sbc 302 pistons.
Pretty sure A.F.R., Promax and Compe***ion Products sell 76 cc aluminum heads, would have to call them to verify if the chamber works with a dome piston.
Stay with 2.020 valves, pistons probably won't clear bigger valves