Heads for 318

[A100]

I'm rebuilding a 318 for my A100 van and I'm getting flummoxed as to what heads will work best. I want to give this motor a bit more pep than stock and heads seem to make a big difference.
I've got a set of KB flat top pistons waiting to go in so that should raise the compression ratio a bit.
I've got a choice, I've got the stock 318 heads that will probably need (at the very least) a light skim, so while the machine shop is in there I don't mind putting in bigger valves and doing some port matching.
I've also got a pair of bare 360 heads that look like they've already been skimmed (don't know how by much?). If memory serves me correct the combustion chamber volume is 65cc. If I use these I'll need to get valves, springs etc. same as the 318 heads so no change there.
I've read that the larger port runners and combustion chambers in the 360 heads can really hurt the compression ratio if used on the 318.
Would I be better off working on the 318 heads?
Every article on building a hot 318 seems to focus on using the 302 casting heads or using Magnum heads which then presents a whole load of other issues.
I don't really want to go to the expense of aluminium Edelbrock heads.
If the Magnum or 302 casting heads are the way to go, has anyone got a set?
I will be using an ally 4 barrel intake and headers.
Sorry for so many questions but I only want to do this once and I don't want to cock it up.

[Dave Napier]

I put 2.02 and 1.60 valves in a 318 head years ago,along some mild porting. They ran ok on the Challenger (14.0's @ 96). My wife (Cath) has a '68 RHD Barracuda which has a mild 318 in it. We used 302 heads this time with the 1.88 and 1.60 valves, ported and the intakes opened up to 360 size. It's gone 13.88 @ 99. I think the 302's are better suited for the 318 with mild, under .500" cams, they used to be for sale as "high swirl" heads with an M/P part #. I have an old mopar performance book with the test and they out performed the pocket ported 360 heads with the 2.02 and 1.60 valve.
Oh, the Barracuda has 3.23 gears in it, 3.91's or 4.10's would really wake it up I reckon. I got the heads from the states along with load of other stuff so the shipping wasn't too bad. Hope this helps.

[A100]

Thanks for the info Dave. I’m starting to think the reworked 318 heads will work better than the 360s. The 360 heads were CHEAP so no great loss if I don’t use them. I’m sure someone on here could use them.
If I can get hold of a set of the high swirl 302 heads I’ll use them. Not exactly growing on trees over here tho !

[Dave Napier]

If you stick with the 318 heads and don't open the intake ports to 360 size you are limiting your choice of intake manifolds. Pretty sure we used a 273 / 318 port sized Edelbrock performer D/P manifold on the first 318, unfortunately I think it's been discontinued. The 2nd 318 we used a performer RPM, we had to open the intake ports up to the manifold size (340 / 360) and work round the pushrod pinch.

[A100]

Thanks again Dave
Good to know.

[mygasser]

the loss of some compression with the 360 heads is more than made up by the bigger valves and port sizes. plus as mentioned there's more manifold choice for the 360 port size heads. no brainer to me.
neil.
ps your higher compression pistons will combat the loss of the 360 size chambers.

[A100]

Thanks Neil.
When I first got the 360 heads it seemed like a no brainier to me as well.
But then I started reading all the 318 build articles again and managed to confuse myself (not difficult at the best of times). Hence the questions.
I’d really like to a set of 302 heads but that doesn’t seem like an option that’s going to present itself anytime soon so the 360 heads are looking like the favourites at the moment.

[Dave Napier]

the loss of some compression with the 360 heads is more than made up by the bigger valves and port sizes. plus as mentioned there's more manifold choice for the 360 port size heads. no brainer to me.
neil.
ps your higher compression pistons will combat the loss of the 360 size chambers.

Only if you are exceeding 7000rpm and / or 400ci (and then there are better choices). Below is the reason why the 302 head is popular on a mild 318. The 360 head will improve it but the 302 head is better in this application. HTH's

[A100]

Thanks again Dave.
High RPMs makes a lot of sense for the 360 heads given the larger port runners. The search for a set of 302 heads begins !

[Dave Napier]

The 302 heads were used in '88 to '92 5.2 Dodge rams (pre Magnum), you might get lucky if someone is breaking a ram of that era.
The advantage of the 302 head is port velocity, the higher speed air flow helped with venturi signal and fuel atomisation. The caveat is in the above, a mild street strip application. IIRC Car Craft did a "Basin Blue" 318 Duster build using those heads and got it to run low 12's, at the time my then 440 Challenger was only running mid 12's

[A100]

So armed with all this info, modded standard heads or better still 302 casting heads are the way to go for a 318 application. Or if your pockets are deep, fancy aluminium heads.
Anyone breaking a late eighties / early nineties dodge ram?

[mygasser]

the loss of some compression with the 360 heads is more than made up by the bigger valves and port sizes. plus as mentioned there's more manifold choice for the 360 port size heads. no brainer to me.
neil.
ps your higher compression pistons will combat the loss of the 360 size chambers.

Only if you are exceeding 7000rpm and / or 400ci (and then there are better choices). Below is the reason why the 302 head is popular on a mild 318. The 360 head will improve it but the 302 head is better in this application. HTH's

yes but my answer was based on his choice between the original 318 heads and the 360 heads, both of which he says he already has. so of those 2 i stand by my choice to use 360 heads
neil.

[mygasser]

it should be 'black friday' sale time at speedmaster soon. their ally heads are pretty close to being edelbrock copies but much cheaper. on black friday they're down to almost half price too. they have deals including the matching inlet too.
neil.

[Dave Napier]

yes but my answer was based on his choice between the original 318 heads and the 360 heads, both of which he says he already has. so of those 2 i stand by my choice to use 360 heads
neil.

Fair point.
I managed to get a set of refurb 302's with the the 1.88 160 valves, ready to go for $500. Some small speedshop was selling them on Ebay USA, they had a few sets for sale and I got in touch direct. Shipping is the killer but I got them over along with some other stuff.
The 360 heads are bare, by the time you open them up for 2.02, 1.60 valves, pocket port, skim etc, with all the hardware you could have well over a grand in them using decent, new stuff. There would also be room to "grow" with them.
Like you say, it may be more viable to get aftermarket heads, the OP would need to weigh up the costings.

[mygasser]

yes but my answer was based on his choice between the original 318 heads and the 360 heads, both of which he says he already has. so of those 2 i stand by my choice to use 360 heads
neil.

Fair point.
I managed to get a set of refurb 302's with the the 1.88 160 valves, ready to go for $500. Some small speedshop was selling them on Ebay USA, they had a few sets for sale and I got in touch direct. Shipping is the killer but I got them over along with some other stuff.
The 360 heads are bare, by the time you open them up for 2.02, 1.60 valves, pocket port, skim etc, with all the hardware you could have well over a grand in them using decent, new stuff. There would also be room to "grow" with them.
Like you say, it may be more viable to get aftermarket heads, the OP would need to weigh up the costings.

yes the shipping costs are mad these days for sure.
he said he'd rebuild either set he had so similar costs there as expected. plus the stock 360 valves are a useful step up in size from the 318's. they'll help to give the 'bit more pep' he's looking for, it'll never be a race motor or he wouldn't be building a 318.
neil.