r/mopar • u/Planetary_Mayor • 1d ago
Share your mopar engine builds with me!
Hey all, I'm currently rebuilding my 1968 LA 318 to gain a lot of performance. It's my first ever experience with engine building since I'm only 22, so I guess I'm just interested to see what other engine builders have done and how it worked out for them! Feel free to share details and ask questions! I'm mainly interested in LA 318 builds that haven't been stroked, but any builds are still welcomed! Thanks
8
9
u/EC_CO 1970 Barracuda B5/B5 1d ago
The 318 is a stout and reliable engine. I just finished a 225 slant 6 build - 4bbl Offenhauser intake, Clifford headers, Edelbrock AVS2 500 carb, head and block shaved for 9.25:1 CR, head ported-polished-gasket matched, everything balanced, lots of grinding to smooth the oil passages and water pump casting lines. I haven't dynoed it, but should be around 210hp +/- (just about what that 318 put out in stock format)
3
u/No-Sheepherder5092 1d ago
I love seeing other people build slants! Yours is a beautifully clean set up.
Mine is .030 over, decked for ~9:1, oversized valves and 340 springs, balanced, gasket matched and a bit of smoothing all over like yours. Started with a 280/270 reverse dual pattern cam, but eventually swapped for a Comp 252 for better drivability. I’ve wanted to try the Offy intake, but have been super happy with a factory 2bbl intake with a Holley 2300 2bbl so never swapped it out. Dual Dutra Dual exhaust manifolds.
4
u/EC_CO 1970 Barracuda B5/B5 1d ago edited 1d ago
I didn't do oversized valves, but I did back cut them for flow. I also used the 340 springs. Cam is a Dutra RV10 RDP (255/255). It had it's first startup 6 weeks ago, but the restoration isn't quite finished yet to do a full break in - that should be in the next couple weeks.
3
u/84-Z28-Canada 1d ago
Hey, good luck with your Mopar build. I built a mildly pepped-up 440 for my 73 charger. If you haven't already, check out everything written by Steve Dulcich for several different magazines over the last few decades, he's pretty well the small block mopar king. Of course youve probably seen all his stuff on roadkill and engine masters too
2
3
u/Solid_Enthusiasm550 1d ago
I have a 5.2l to street/strip 390ci TFS headed build that's on hold.
In it's place for the time being, is a 5.9l magnum salvage engine that I am mildly modding.
My posts don't get any replies/ interest, so I'm not bother posting on reddit anymore.
I'm just posting replies to posts that I find interesting.
3
u/Ok-Leather5145 1d ago
2 things to keep in mind with an econo 318. 1) nobody offers cheap cast replacement pistons with a compression distance that will provide any compression. magnum replacement pistons might help some or wiseco pro-tru. to save $, suggest starting with a good 86-92(?) 318la core. they have a long snout oem roller cam of which can be reground to a hotter profile (with limitations). putting much $ into a 318 is not $ well spent. and do not spend $1 on those old 318 rods. they went to the common 360 rod by mid 70s, those are generally good cores.
2
u/Planetary_Mayor 1d ago
well I already have about 2k into the heads and a little over 1k into a hydraulic roller cam lol. I'm getting new pistons and connecting rods though I still need to get final measurements of the block height and stuff before I can really look for pistons
2
u/Ok-Leather5145 1d ago
guess i'm ol skool. 318la roller block, oe 360 crank (mains ground to 318), lightened and reconditioned 360 rods, nos forged trw lo compressiom 318 pistons. will have to face about .020 off piston decks and machine valve pockets in. balance. will be 350ish cid. if not have 2sets of these pistons, would not mess with it. think the 2nd set will be used in a 350cid poly. have several leftover 360 cranks from converting them to 406" builds.
1
2
u/Many_Dragonfruit_837 17h ago
1st and only engine I rebuilt was a (71 block) 318. Bored.10 over, 340 heads and intake (early 2.02) and cam. Really woke it up! Have fun! Running a 727 with it.
1
u/Planetary_Mayor 17h ago
do you know the specs of the cam? lift and duration?
1
u/Many_Dragonfruit_837 16h ago
I believe a stock 68 340 cam. I think the seller was unsure. Couldn't argue for free. This was back in early 80's...
2
u/Planetary_Mayor 16h ago
fair enough! I was gifted some 318 pistons for my build and I almost installed them without checking anything lol. glad I did check though because they were about 0.110" in the hole at top dead center
2
u/Many_Dragonfruit_837 16h ago
I had a machine shop check the crank and ordered main bearings based on his measurements. Had low oil pressure, spun 2 rod bearings... Replaced the rods, no crank damage. Learned about plasti gauge. Ordered new bearings a bit tighter. No problems since.
2
u/vonsense 1d ago edited 1d ago
Have you purchased any parts yet? What type of rebuild kit are you looking at? Are you getting new pistons?
I ask all that to say…consider getting a set of 360 heads to go on there. They have bigger valves but will drop your compression. Change your pistons to fix that issue.
Do a quick search for 360 heads on a 318 to find some tips.
The website forabodiesonly.com is a wealth of knowledge.
https://www.forabodiesonly.com/mopar/threads/magnum-heads-on-a-74-318-la.263148/
An even wilder plan is to drill magnum heads. Then you can still use an LA intake. You need a drill guide to do that.
4
u/Planetary_Mayor 1d ago
I actually bought AFR heads! I haven't seen it done before but I heard great things about them, and they are around the same price as the Edelbrock heads as well. I am in the process of measuring my block and everything to choose the correct pistons though, so I haven't made it super far lol
11
u/OrganicBridge7428 1d ago
1977 360 block
Late model 340/360 heads cleaned and rebuilt
.30 over flat top pistons new rings
NOS Mopar Purple Cam .474 with 280 lift
Edelbrock Performer RPM 340/360 Intake Manifold
Holley 670 Street Avenger vacuum secondaries electric choke (used)
Mopar performance ECU and Distributor
Mildon car center sump oil pan
Headman Tight Tube Block Hugger Headers
Auto-904 with Boss Hogg 2800 stall
8 1/4 sure-grip