Hey guys looking for a little help picking a cam my 91 rs. Ive picked up a set of 87 corvette heads that have been completly re worked by a very reputable machine shop they have been milled to 58cc combustion chambers. Along with the heads i will be putting on a better flowing intake manafold and headers and y-pipe. Im looking for a cam that will match my other parts well and keep the motor reliable and the car very streetable as this is my daily driver. I was hoping to get some where in the 250-275 hp and tq range with decent 16-17 mpg gas milage. Any help would be great. Thanks in advance guys.

 

I'm not familiar with corvette powerplants in 1987

did they come with a 3.75 inch bore like your 305?

 

thats funny cause i have been thinking of doin the same instead of buyin a 350..im just gonna rebuild the top end of the engine. well no need to make a thread now haha.. keep us posted i wanna see what happens from here.

 

I'd get a set of 305 vortec heads instead, they'll outflow those vette heads.
If you go w/ the vette heads, remember they have the old style intake bolt pattern, not like the others which changed after '86.

 

I had seriously thought about vortec heads but chose the vette heads because they had the correct cc combistion chambers to keep my compression just below 10:1. Just waiting on some funds for the rest of the parts. Im recovering from a broke leg and really put a pinch on my plans. As far as the motor the heads came off of orginaly im really not shure im no corvette expert at all. Appreciate the interest guys.

 

I done some digging about the engine the heads came off of and it was a l98 350. Also i was wandering if there should be any concern with the size of the valves in the heads, as far as them being to large and hitting the side of the cylinder? Sorry if thats a dum question im kinda new to picking parts. lol

 

1.94s & 1.50s.

 

1.94 and 1.50 is the limit? my heads have 2.02 and 1.60.

 

Thats what the vettes came with.
You might have to clearence the bore for those heads. You are putting them on a 305 arent you?

 

yea its a 305.

 

I would stick with a roller cam, but keep in mind to get full power out of your new combo ECM tuning will be required. Higher fuel pressure (stiffer spring 15 to 18PSI) should also help at WOT. For 305 build like you are describing LT1 cam from Y/F-body is hard to beat - money, performance and easier to tune. You'll have to read on LT1 cam swap - there are several threads on this subject.

//RF

 

304 BORE 3.736 STROKE 3.48

350 4.00 3.48

I dont know for sure but there are posts that speak of possible interference issues?

 

FROM 83 CROSSFIRE POST:
In most cases the chamber ends up bigger than the bore, but the valves clear... what you absolutely don't want is unsupported head gasket exposed to the chamber. 2 possibilities with the head gaskets:
- the best way: get one cut with the 305 bore diameter and notches where the valves are (I've had some custom cut by cometic, have drawings of them somewhere)
- use 350 head gaskets (with a 4.0x" diameter), they will increase the dead crevice volume between the block/head making the combination slightly less efficient and "dirtier" but for the setups that you guys are talking about (especially with the fairly low performance stock type heads) you'll never know the difference (and it will be the difference between a $30 and $200 set of head gaskets)
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Thanks for the info on the valve clearnce. I will do some reading on the lt1 cams. After the build is completed i will have the car dyno tuned by a local shop.