I have a sweet running, factory stock, 76 360 that that I would like to do some upgrades on. I picked up a factory spreadbore intake, 625 cfm AFB, 1 5/8 headers, Comp XE268 cam and springs. I know compression is going to hurt performance, but it's not in the budget to buy pistons. This engine is in my 68 Dart, 727 with factory high stall converter and 3.23 gears. Will this set up work? It doesn't run bad now, I would just like a little more.

Sounds like a nice combo. I like 3.55 gears in my street car if you have some laying around.

Contrary to what you are likely to hear you will see a good improvement. You will hear you should do this or that but on a budget ou will do fine till you decide to step up

definitely get the right cam considering the low compression (I ain't sayin the 268 is not as I ain't a cam guy but confirm it is a good choice). Definitely dial in the dist subsystems/mixture/free flowing exhaust (takes a bit of creativity to have good flow but quiet enough to suit you (& your neighbors)

I've got a choice between 3.23 and 3.91's. I've run 3.91's behind a few big blocks, but it's a little steep for what I want on the street. I really don't know how I managed to live with 4.10's in my 69 GTX, but I guess when you're 23 you can put up with a lot more than at 63! lol I have seen Speed Pro h405cp pistons with rings, on ebay for $120, but it is only an increase to 8.6 with my open chambered heads. I agree that it's better than 7 something, but will I really see much of an improvement?

Get the h405cp's and and with calculated decking you can get over 9:1. If you really want to wake it up, add some Magnum replacement (EQ) heads and burn rubber!

if it is running now & you dont want to pull the eng & go thru from head to toe (& it sounds like you dont), you just want bolt ons, what Doug said I would consider some JY mags. you would need mag rocker assys/oil thru pushrods (not sure if the JY eng would have the right length p rods but the guys here know) and a mag intake or mod yours. it would take some doing

The specs on the h405cp's say you can get 9.1 with 63 cc heads and 8.66 with 68 cc's, which is what I think my heads are. I just hate to tear into something that runs so sweet. It doesn't use a drop of oil. Guess I have to decide how much of an increase in performance I want. Think I'll bolt in what I've got and maybe add better pistons this winter.

VG plan. People get caught up in this & end up with WAY too much down time. Summer is here! If desired build another killer eng at your leisure in your shop as time/money allow & that will let you do all of the little time consuming tricks that add up

The low compression and that cam will be soft on the bottom end but if you already have it you can install it and advance it about 4 degrees with an adjustable timing chain or offset key, even better if you know how to degree it and set it a few degrees advanced. It will run pretty good this way and the 3.23 gears I done one real similar, I even added magnum heads to that motor later and the gain was worth it. For pushrods you can get some 351 ferd PRs made for a factory roller cam engine aroun 1996 or so, you can actually get a nice hardened set of eddelbrocks in this length for real reasonable. They are not perfect but close enough to get ok geometry on a budget. I even used the GM V6 valve springs on that engine with the XE268 cam when I put on the magnum heads and it would pull cleanly to 6000. When compression is at a premium I buy one MLS head gasket (mr gasket has em cheap)seperate the layers and run the two thin layers coated with copper spray as individual steel shim head gaskets for a good duplicate of the factory steel shims, so far no issues doing this. You need to make sure your head and deck are TOTALLY clean and free of corrosion to make sure they will seal this way.


Disclaimer.... Some of my methods are not the best possible way but I have learned quite a few tricks to make someone faster on a shoestring budget so discuss them with others and use them at your own risk.

the 405cp's arent worth it imo, especially if youre on a budget. been there, done that, years ago I let a machine shop talk me in to them. did the 405'sm then needed decking to get within a whiff of 8.5:1; with decking then intake milling to get it to fit, when its all said and done you could have bought the right pistons.

If you don't want to spend the money then time to rework the dist get all the timing in by top of your stall the last factory high stall I had would flash to 2200so figure there and then get your total as high as you can until it talks back{ ping, won't crank, etc then drop it back 2-3 degree's.A 650 dbl pumper would round it out nicely with close to stock jets I prefer 70s frt 74-75 rear.

Last but not least you need gears 3.91 are the way to go but I have run 4.30s and 4.56s with tall tires . Sound busy but should not hurt iti have run mine for hours on end on hot days and never gave a whimper I guess 27 years out of engine not bad for a home garage rebuild

Dave, good info. is that the mr gasket 1121 gasket?