Hey guys, What machine work will I have to have done it I want to take out my heads and mill off those stupid swirls blocking my ports? Would I want to throw some new springs on there too? I am just curious. Otherwise I would buy a set of Double hump corvette heads for 300$ from my buddy. I think they would really free things up and would be much easier on me.


Either way will those corvette heads bolt right on?

 

you can't port out the swirl ramp in your heads, from what I understand there is a water jacket in that general area. Just get a bowl blend, 3 angle VJ back cut valves and a full port on the exhaust side. should do you just nicely. Those double hump "vette" heads will make you lose a good deal of compression. 58cc vs.76cc. that will kill power in most cases.

 

'Trey - check casting number of those heads first. Most double hump or camel back heads had 64cc - for example 462 heads. If you are going to put them on you will loose compression - hence power. Also, many of them came with large intake valves 2.02 which may come close to cylinder bore of your 305. The other bad thing is that camel back heads lacked accessory holes (most of them, but not all). By the time you are done with machine work on those older castings you are much better off getting a modern after market heads that were designed for 305 from the beginning. It is a bit more money, but you have to figure a total cost of ownership. I would not use camel back on todays engines - they are not as good, unless you are doing 100 percent restoration job on a 'vete or period correct 1st gen.

//RF

 

Imo I wouldn't waste time on the stock heads or the humps. Just find you some vortecs ( from a local salvage yard) and get a good 3 angle valve job with good springs. Also have the machine shop set them up for your intake bolt holes. You'll have a good start if you want to upgrade the motor in the future.

 

You really can't use your stock intake with vortecs. even if they are drilled for the factory intake the runners on the heads are to tall for the stock intake to handle. Meaning you'll either have one hell of an intake leak or worse, coolant leaking into the engine.

 

Yeah your right with that. Well I've built some 305s, LG4s, TBIs and TPIs and what i did with my old LG4 was to port the stock (non swirl port) heads, 3 angle valve job, ss 1.94 1.50 valves and milled down a bit. That motor with a cam, intake, headers, exhaust and chip made enough power to beat TPI 350s and 305s that I came across. But I ended up building a 355 in the end. Wish I would have done that in the first place.

 

Can I use my 305 TBI unit with a vortec intake off a 305 truck.. I am trying to find a u pull it with a truck that had tbi vortec I guess. I am looking for 275-300hp so am guessing a ringed 305 with heads cam and exhaust as well as intake will get better than 12mpg and make good HP, I really like having a 305, if you had a really powerful one it like an underdog. Throw a cam in it when I put the heads in and run it while I save upfor an EBL tuner....

 

Thats a good long term approach. Just couple of notes.

Stock truck vortec manifold is not your performance oriented piece - GM performance has one, but it is pricey (+$300). Alternatively you can get Performer Edlebrock Vortec with a TBI adapter plate. In both case check for hood clearance.

Stock Vortec heads will not handle over 0.480 lift - this will require a trip to a machine shop and new springs (you'll need them any way)

To be fully emissions compliant you'll have to plumb exhaust gases from exhaust manifold for EGR functionality - there are couple of writeup on this subject (google it).

With a full exhaust, better intake, minor port job and a cam should be able to hit 250+HP with that combo

To support higher power levels you may need to bump up fuel pressure from 13 PSI to about 20+ - this may require a new fuel pump

EBL is the way to go. Also consider WBO once you get your combo going.

Final word - plan, read, research before spending any money or turning wrenches.

//RF