ok heres the deal, I have to engines available for me to build up. I have a 69 327, casting 3956618. And I have what is believed to be a 400 Pontiac, although it could be a 455, havent had a chance to inspect it seeing as it is out of state. Just looing for opinions on which to build.

 

First off what are you looking to accomplish? What will you be using the car for most of the time? The pontiac motors are ore expensive to work with as far as parts and such. But the saying is " There is no replacement for ... ohh you know. 400 or 455, slight difference there but 500 horses could fit under you hood that way. The 327 is one of the best engines all around that GM every produced. The weight difference of the 327 and availability of swappable parts make it a good choice. I have had all three and my favorite was the 327 as it was smooth and responsive but I had fun with the Pontiac SD455 as well.

 

What's your budget?

Some of us romantics like the Pontiac engine better. There is a sticky specifically for this in the engine swap forum.

The 327 is the easiest approach. It's a drop in, and with the 305 crank and rods that you already have you are one set of cheap pistons away from having a 350.

Now that you have a 350, you can use your existing LG4 heads to make some good power. A little time from you in your garage and those heads are ready to give you some serious power.

Now you are only a carb and ignition upgrade away from a really great setup. It's also easy to bolt it in and all of your LG4 accessories bolt right on. Not to mention fuel lines and exhaust...

You probably didn't realize that your old 305 was so valuable!!

If you have a lot more time, you can do the Pontiac without laying out serious cash but you will trade that money for LOTS of time spent fabricating, measuring, and hunting for used parts to boost the power on your old poncho mill.

I like the Pontiac engine better, for many reasons. It really depends on the money you have to spend and the time you have to invest.

 

You are lucky too have such a problem.

 

It's not hard to find a Pontiac V8 if you are looking. Some of my personal favorite spots are your local demolition derby guys. Mostly they pull the "other than chevy" engines out of their cars and put them in a pile to scrap them. They usually run their dedicated sbc over and over in their cars...

If you talk to them they will give you a call when they are pulling engines (most are decent runners) and sell them to you for just over junk price. I was getting engines for 50 bucks and less very often. Of course, you just treat it as a core, but hey, you're gonna rebuild your used chevy if you have one...

 

Ok so....maybe it would help if I posted up some more info on my plans.

If I build the 327, I would be stroking it out to a 383, keeping it carbed, and go with balanced and forged rotating assebly.

If I build the Pontiac 400 I would be mking it into a 461, probably carbed, forged and balanced too.

I know the 400 should be able to make power with less stress. But is it worth it to build the poncho?

 

I don't think that there is an issue with "worth" for either engine...

If you modify an engine for your car it most likely will not be worth more than the sum of the money that you put in to it. You are bound to lose money...

So? Why are you building an engine based on worth? Pick the one that you want, build it, and enjoy your car. Either engine is going to cost tons of dough and will require lots of tuning (even carbureted) to get it just right.

The closest answer is that neither engine will be worth more than the other when you are done. They will both be used, modified engines.

 

yeah tough question. go with ready available parts to build quick 327 which many of even our grandfathers rodded out .or go with the not so easy 400+ which stated before is no easy fit in our cars. really u could have the 327 pushin' 12's in no time or take time and build an original with the pontiac......orange or blue. it's up to u! i'm a gator so i get the best of both worlds but then again i'm a novice.

 

Actually the 400's are pretty easy to drop in the conversion parts cost under $200 to mount them the hard part is if you want headers. You can score a decent mid 70's 400 block for dirt cheap and just drop a mild cam in them and they wake up just fine. Plus you can say you have a REAL pontiac engine in your firebird. That and they make awesome torque

 

[QUOTE=KrisW;3392398]



[The 327 is the easiest approach. It's a drop in, and with the 305 crank and rods that you already have you are one set of cheap pistons away from having a 350.]

There's only one problem with that statement. Even though the 305 crank is the same stroke and journal sizes as the 350 crank, they're balanced differently. Been a lot of arguments about that one on here over the years. It requires fairly expensive re-balancing to use a 305 crank in a 350 supposedly. So it's actually cheaper to just use a 350 crank. The crazy part is GM even used the same casting# on a lot of them, whether it was in a 305 or a 350. I've got one of those cranks sitting in the shed, and I can't remember for the life of me whether I pulled it from a 305 or a 350. Lol. The big Pontiac motor is definitely the better choice as far as the "Cool" factor is concerned. But it'd be a ton more work and headache. Even after you manage to get it all mounted and plumbed, you'd probably have to get some good, stout coil springs to handle the extra weight of the bigger motor. The old saying, "It's not easy being different", definitely applies here!

 

[QUOTE=Pat Hall;3461666]
Actually theres a couple guys on here who have done the 400 conversion and just used their stock 350 springs and they say they haven't noticed any sagging or anything I don't think theirs really that much weight diff between a 350 and a 400 block. As far a plumbing whats the diff? Standard GM stuff, most mid to late 70's cars had a normal GM HEI setup with vac advance, and a 4 bbl carb. If you can't hook up a standard HEI and plumb fuel lines from your frame rail to the carb you shouldn't be attempting an engine swap anyway. I think you can just modify stock 2nd or 3rd gen rad cooling hoses to work.

The conversion motor mounts are out there they go for around $90 and they work with the regular chevy V8 rubber frame mounts
(http://www.pontiacgroup.com)

If you want to use your stock 700R4 JEGS makes a BOP to Chevy trans adapter for $60 (I think theres one sticks too) (http://www.jegs.com/webapp/wcs/store...0002_751074_-1)
You will also need an after market adapter for the lockup function which are like $100~150 B&M makes one along with most other trans companys out there. That or just rig a switch for manual operation.

As long as you use the proper conversion mounts and you use the stock intake or one that doesn't have a radical rise on it like a regular edelbrock performer the air cleaner will clear the hood just fine. You may have to cut down the alternator adjusting braket a little but they are longer than they need to be by at least an inch or two anyway.

Some of the stock manifolds which I'm told flow pretty good for stocks will work but you either have to modify your Y-pipe or get a new one made up to work with the system.... Now if you want headers thats a different story you can either pay around 500 for some custom ones or modify a set made for a FULLSIZE (bonniville, catalina, ect.).

Thats pretty much it just have to redo the wiring maybe switch out a sender or two for the ones on the 305 / 350 block to get the signals right.

I guess what I'm saying is its really not as hard as its made out to be.