349 CI on the cheap

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BJR Racing said:
Terry,
302 heads are out there and sould be in most junk yards, and will work the best on a 318 but if a 349 engine is what your after then the 360 1.88/1.60 valve heads will work better
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If the 302 heads were gone over and the 1.88 and 1.60 valves were installed would they still work well on a 349? I already have a set of 302s that came on my donor engine and I like the idea of closed chambers.
 
Sure they'll work but you'll be limited on the amount of rpm's that you'll be able to turn with the engine. Because of the small port voulme, this is why I suggested the 360 heads be used on a 349 engine. If you looking for a good torque monster for the street then this would be the way that I would go also, but like I said the engine would be rpm limited with the 302 heads. Unless you have a ton of duration @ .050 but then this isn't very streetable.

I suppose you could use something like a 240-250 @ .050 with a 110 or a 112 lobe seperation and a 3500 converter and it would work. As the stroke will eat up some of the duration.
 
Thank-you for your help and insight. I picked up a set of 360 heads and am just starting to put together a parts list for a streetable 344. You opened my eyes to a power output I didn think was possible with that kind of investment. Sorry for any bad grammar or spelling, the letters are overlapping when I dont want them to, cant turn it off right now, or dont know how...
I hate computers sometimes...
Tom
 
Hey Guys - as Bobby says, I have a flat 13sec 349 at 10.2:1 comp.

My problem all along has been Piston to Valve clearance at zero deck.

I can tell you that even with my fairly mild .495 lift [email protected] cam and lightly skimmed 360 open chamber heads, , my valves hit the slugs big time, and we had to do some 'shade tree" cuts in the slugs to get away without dis-assembling the engine.

(see pic)

Bobby - How deep did you notch those slugs of yours, because I was "advised" by United Engines that i shouldn't notch the Silvolite cast slugs at all when I was considering rebuilding the 349......

P1010047.jpg
 
Mal,
The notches are .200 deep, this is good for NA engines and for NOS .150 should be the max for the valve pockets. We've been valve relieving cast pistons for years without any problems, but we don't run cylinder pressures over 175 either.
 
On the issue of what pistons to use- the guy that built mine used forged SP226P TRWs with 100th off the top to achieve the zero deck - trouble is he forgot to measure the P-V clearance at overlap.......

Those hand ground reliefs are about .055 deep, so a forged slug with a lower comp height that needs less off the top would probably work pretty well.......
 
Mal,
If the piston comes out of the block just do like I did and chamfer the top edge ans let it stick up into the open part of the chamber. You just have to have the valve pocket large enough to get around the hump in the head where the valve seat is casted in the head. So a 2.10 valve pocket should be enough for a 2.02 valve. This is what I did on the cast pistons in the pictures, I also chamfered the edge of the piston to put it .015 below deck so I could run a thin gasket and this allows the piston to act like a dome style going up into the chamber and creating a quench like a close chamber head.
 
I suppose you could use something like a 240-250 @ .050 with a 110 or a 112 lobe seperation and a 3500 converter and it would work. As the stroke will eat up some of the duration.
Click to expand...

In regards to this comment Bobby thats close to what i have in my combo and im close to getting it to the track. Mines a 256 @.50 108 lsa and a 3200 stall with 3.55 gears @ 3150lbs including driver.

Hysteric
 
I still have to finish the heads for mine and may be able to get to them by the end of the week comming up. I would like to have it in and running by the end of the month and have a time slip or two. I'm realistically looking for some mid to upper 6 sec. 1/8 mile times. This way I can take the car to Commerce next year for the nationals, and run in Super Street, which is 10.90 1/4 mile. 6.50 = about a 10.40 1/4 mile, 6.70 is about a 10.70 1/4.
 
i wish i would have seen this thread about 6 months ago i could have saved about $8000
for the price anybody building a stroker is crazy this would save a fortune and get equal performance
 
I never really sat down and figured it out but I would guess it would be about $6,500.00 complete ready to run. This includes all machining and porting and all parts from intake to pan. And by cutting .050 off the pistons makes it very streetable. This combo shows to make 626 HP @ 6,500 and 545 ft. lbs. @ 4,500 and 5,000 rpms. 222 hp and 389 tq @ 3,000 rpms but this is more of a race engine than street. This engine will have small chamber heads and the compression will be 14.68:1 but the cylinder PSI will be in the 170 psi range due to the cam being used. If a smaller cam is to be used then the larger head like a 360 head and a thick head gasket would be in order. This would put the compression ratio in the 10.25 to 10.5 range with minimal decking of the heads or block.
 
BJR Racing said:
First we'll start with a 318 block (rebuilder) as they are plentiful, then we'll get a 360 crank and turn the mains down to 318 specs. this runs about $200.00 to do. We are going to use the factory 6.123 rods, and low compression 318 pistons which are 1.72 compression height. Next we are going to align hone and deck the block to clean and square deck all 4 corners. Price will vary as to your local. This is more info on what to do and not priced as price can vary. So now we have a block that measures 9.570 after decking .030. As most used blocks are generally out .020 to .030 from core settleing and thermal cycles, some may be taller as they are only castings. Now this is where we are 9.570 actual deck height less the rod lenght, and the compression distance, and stroke. Half of 3.58 is 1.79 on stroke.

9.570-1.79=7.780 minus rod lenght of 6.123= 1.657 less the compression distance of 1.72= .063 above the deck. Now we'll take a corteco head gasket of .055 which now we have .008 above the gasket. Or for racing use a .022 mopar gasket and have .033 more compression for a total of .041 above the gasket.

Next we'll go to the heads, for a 349 CI we'll need the 360 heads to get enough port volume and air flow. By my calulations we'll need 166 cc's of port volume and 266 cfms to supply enough air and we'll be useing the 1.88 intake valves and 1.60 exhaust valves to help keep the port velocity up. This is fairly easy to get when mildly ported. As for the chambers they have been in the .095 to .105 in chamber depth stock, at the area where the quench would be. So now we have a positive deck of .041 with the gasket in place, or .008 depending on which gasket is being used. In this case we'll use the thinner gasket so we'll be .041 above the deck. Now the deck is .095 less the positive deck of .041 and we now have a quench of .051 so we'll deck the heads to true them up, generally this takes .010 to .012 so now we have a total quench of .039 to .041 which is what most would like to have as total quench. This now yeilds 12.21:1 this is why this is a race setup, the thicker head gasket will yeild about 11.5:1. If it doesn't take as much to deck the heads or the block then this will change to a lower compression and be more streetable.

Next we'll go to the camshaft, for our example were useing a comp cams .540 /300 drag race cam with 255 @ .050. For this cam the pistons will have to be notched, so we notched them .200 as the pistons are forged and are .400 thick. This is about as far as you can go safely. We'll be useing 1.6 ratio rockers so the lift is .576 but the lash is .026 and we have to subtract .010 for the loss of valve lift due to the grind for mopars. Now we have a actual net lift of .540. So with the valve reliefs we should have .100-.130 valve to piston clearence depending on the gasket thickness.

Next we'll go to the intake manifold, this I leave up to the end user for what they want. But for our application we used the M-1 intake as we had it, from another engine. And we'll top it off with a holley carb 850 cfm with 83 and 88 jets and no power valves.

Next we went to the exhaust as we used hedders the were from dyno-max as they were inexpensive and could get them locally. They were the 1 5/8 street type as we didn't want to get to large as we only have 349 CI's and the bore won't support much more, and neither will the heads.

So now to some this up we have a 318 with a 360 crank and stock rods and pistons of the forged type. Stock type heads with work done and a M-1 intake and a street type hedders. A good cam and valve train and oiling system to support this type of engine. The preliminary tests have shown 578 HP @ 6500 and 507 TQ @ 5000, and 506 FT. lbs. @ 4500. So it has a nice broad torque curve. Even in lessor trim it should still have over 500 HP and 450 in torque and be streetable.

Our cost in this engine with all machine work and parts we have $4,400.00 invested. A cast piston version with less cam would be roughly $500.00 less. Not bad for a engine like this when a crate engine costs about the same and wouldn't have the quality or the power.

But it does show what can be done with available parts and some time if your a do it your selfer, other than machine work. I'm guessing that you may be able to save $1,000.00 or more.
This is for information only and just something that we wanted to play with.
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This is a great idea! Now I have a 318 that was punched out .040 because I was going to do this build
http://www.popularhotrodding.com/enginemasters/articles/mopar/0667em_mopar_318_engine/index.html

But I like yours better. Now what kind of effect will I get where my block is 40 thou over? Positive? negative? I am just like the rest of the human race and want bigger, faster, better.
Thanks!
 
Hey Bobby,

I steered Jeff in the 349 direction. I am going to supply him with a set of heads and a 360 crank. Everything will need to be freshened. I believe he can use the 318 rods he has if I am not mistaken. He wants an engine that has plenty of grunt but still will run on 91 octane. He will have to buy some pistons. What would you recommend? The cam should be chosen with street manners bordering on the higher end. He has a standard tranny in a 71 Demon with a 8 3/4 rear. At present I believe he has 3:23 gears but may move to 3:91's.

Jack
 
Thanks Jack....what he said. The cam I had looked at was a comp xe275hc, but that was only because it was used in the other build. I had looked at a set of flat top Hypereutectic pistons, but again, what would you suggest? I will give you a call tomorrow afternoon, i missed your call tonight.
 
Jack,
He doesn't want to run the small 318 rods unless they are the truck or HD units and at that point they will be 360 rods. The cheapest way to do this engine is to get a stock replacement piston and cut about .075 off the top and this will put you about .010 below deck. This way the compression won't be too high and the cam won't need any valve to piston clearencing.

I'm trying to finish up the 344 engine but I machined the pistons differently as to have compression, and used small chamber heads. My compression ratio works out to be 14.96:1, then with 107 OL cam and the cylinder pressure comes out to be 180 psi.. With all the tricks that I could find and use the engine on the computer aided design (CAD) system shows 638 HP @ 6500 RPM and 542 TQ @ 5000 RPM. This should be enough engine to get me where I need to be in S/ST NHRA. I wnat this engine in and running this Saturday so I can test it on Sunday. But this is if the weather holds out as there forcasting rain on Friday, Saturday, and Sunday.
 
Hey Bobby,

I believe the rods are still good out of the locked up block I have. I will have to have a look tonight. I suspect I will have to break a piston or two to get them out though. I have to look at the heads tonight to, I can't remember if they are closed chamber or not, but I don't think so. We should know what we have to work with tonight and we can go from there to get Jeff his high horsepower, low buck engine. I checked the crank out last night and other than a little rust on the snout it looks good. That is no biggie.
I hope you can make it to the track on the weekend. I would like to know what that engine does in real life. We know all about rain here, it hasn't stopped for more than an hour since last Friday.

Jack
 
Jack,
On the 360 crank it will need to be cut on the counter weights about .100 to clear the pistons with stock compression distance, then rebalanced and you should be good to go.

As for the this weekend I'll let you know asap, I just returned from the warehouse and picked up the final gaskets that I needed and the JG BR oil, so as of now everything is still a go for the weekend.
 
This have been a great thread, I have been torn as what to build for a future motor for my 64 Valiant, since I already have a 72 318 in the car your alls recipes will help me build a great engine for street use. The current engine is a .30 over 318 block , with 3671587 cast head, with 1.88/160 valves, mildly ported, 340 factory Mopar purple cam, windage tray, LD4B/600 cfm, pertronixs, with factory exhaust manifolds....all that gave me a whooping 225 hp with 275 LBS torque.....Wow, with what you have out lined.......I could break the 400 hp mark and scare the **** out of myself.........all with a 318........
 
64,
You really need more than a 600 cfm carb to supply the engine, I don't run less than a 750 VS carb on the street. The TQ were 800 cfm's so why would anyone want to run less of a carb?

Also too you hurt the performance on the 318 by using the 360 heads, the engine would make more power and respond better with a good set of 318 heads with the same work done to them.
 
I thought or read that the the heads I have are 318, I had the heads cut for the bigger valves? I am using the 600 cfm carb because I got a good deal on it and it was new in the box (75 dollars). I would love to use 302 heads and some spitfire headers, have thought of building my own flow bench to port the 302's, unfourtunately the availability of anything Mopar around me is slim, and when anything goes to the scrapyard it is gone before I get there. I have a set of Dak Headers that have some potenial to be cut and fitted. I have had to get creatative with what I could find and afford. One of these days I would like to build a nice street motor out of a 318.....and you all have given me hope it can be done...
I will be reading and taking notes......


You really need more than a 600 cfm carb to supply the engine, I don't run less than a 750 VS carb on the street. The TQ were 800 cfm's so why would anyone want to run less of a carb?

Also too you hurt the performance on the 318 by using the 360 heads, the engine would make more power and respond better with a good set of 318 heads with the same work done to them.[/quote]
 
64,
Your right I read too fast and looked at the casting number wrong, but still the intake valve is too large for the 318 head casting and port volume. The exh. valve would be fine as the 318 head is really hurting on the exh. side more so than the intake side.
 
Well, I have the engine done and going in the car today so hopefully after some detailing I'll have the engine fired up today. Then a change of the break in oil and we should be ready to go to the track on Sunday, but they increased the chances for rain so hopefully it will hold off so I can get a couple of passes on the new engine and get a base line for the car and chassis. I'll know more this afternoon.
 
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