78 Chevy Monza

[63chevystepside]

Im going to get back on the 66stepside now.My first thing on it is to switch the crank from one engine i know is good(350 with low compression pistons for 305 heads that need work on) to the 1975 engine with i think all good but crank-or crank bearings-or maybe where the piston and rod attach? I need to yank out the 75 and get it on a stand-im darn near tempted to bore it 90 over and go all out.

 

[63chevystepside]

Doesn't sound like you needed long slot rockers for that cam, but you have them now should you decide to go bigger someday. I'll also add, as light as that car is, don't be suprised if you don't get 2200 stall out of it. Being you said its 2200-2600 it might, but I have never seen such a range rating either. If were me, I'd have probably ran a 3000 stall and hope to get around 2500-2600 out of it in such a light car. A heavier car or truck might even get more than 2200. Lots of things to factor in when choosing a stall. Still oughta work good with that cam though, just saying, you might not get 2200 out of it is all.

I found a site on here that said stock rockers can only go up to a 470 lift and my cam has a 480 lift-but your right better safe than sorry.The stall is a 2200-2500 sorry if i made a type error. Your probably right on the stall and weight thing but if i get at least a 2200 stall thats where the cam starts(2200-6200rpm)so they should be ok. Wed im going to maybe go weigh it up here at the dump.

 

[hotrodpc]

NO, do not go .090 over on a 350 block. At least not without a sonic test, but I say no anyway. One good overheat, and goodbye block. I'd stick to no more than .060 at max. I really prefer .040 for a daily driver type, but .060 can be achieved easily in most cases.

 

[63chevystepside]

I talked to the regrind cam guy and he said he could get a cam that would go good with those z28 springs that has a 501 lift-292 duration-110 lobe-2500-6500rpm range and thats the biggest cam i can go with those springs-im also actually pondering about get that cam and putting it in the monza then yanking the engine and tranny out of the monza and slap on the headers i got and put it in the trk???

 

[63chevystepside]

NO, do not go .090 over on a 350 block. At least not without a sonic test, but I say no anyway. One good overheat, and goodbye block. I'd stick to no more than .060 at max. I really prefer .040 for a daily driver type, but .060 can be achieved easily in most cases.

ok

 

[63chevystepside]

If i bore it 60 over i can use all the stuff i got already but need 60 over pistons-right?

 

[hotrodpc]

If i bore it 60 over i can use all the stuff i got already but need 60 over pistons-right?

Yep. Are you sure it even needs a bore? If the cylinders are still up to spec, you can just rering it too. I'd also try to avoid those 305 heads. I know, some will tell you that raises the compression ratio, and true that. BUT, they are small valves, and very small ports that will not flow well, so you get more hurt than the little raise in compression ratio helps for a performance motor. Now if you are building low rpm truck engine, where it makes alot of torque at the bottom end for say towing a boat or something, then sure, the 305 head idea is OK, but it will not give much horsepower. Just increase in low end torque. So it will have pull power, just don't be in a hurry. Find you some 350 heads 194/1.72 heads, and go with a flat top piston instead of a dish piston, and there you will make up the more compression ratio. Also when you have the heads worked on, since you'll be using composition gaskets instead of metal shim gasket, go ahead have .010 or .020 shaved off like you did the Monza heads.

 

[63chevystepside]

If i bore it 60 over i can use all the stuff i got already but need 60 over pistons-right?

Yep. Are you sure it even needs a bore? If the cylinders are still up to spec, you can just rering it too. I'd also try to avoid those 305 heads. I know, some will tell you that raises the compression ratio, and true that. BUT, they are small valves, and very small ports that will not flow well, so you get more hurt than the little raise in compression ratio helps for a performance motor. Now if you are building low rpm truck engine, where it makes alot of torque at the bottom end for say towing a boat or something, then sure, the 305 head idea is OK, but it will not give much horsepower. Just increase in low end torque. So it will have pull power, just don't be in a hurry. Find you some 350 heads 194/1.72 heads, and go with a flat top piston instead of a dish piston, and there you will make up the more compression ratio. Also when you have the heads worked on, since you'll be using composition gaskets instead of metal shim gasket, go ahead have .010 or .020 shaved off like you did the Monza heads.

OK then it might be better than if i use the 350engine on the stand already- that had the 305heads on it-its bored 30 over but they are low compression pistons so all i have to do is switch the pistons to 30 over reg pistions slap on the heads from the other 350...the heads on the monza are 194 im not sure what they are on this other one---im still thinking this thing through-i would like to bore it 60 over-put some 10.1 pistions in it-put on the 350 heads and that 501 cam...

 

[63chevystepside]

I weighed it today-it weighs(drum solo)---2800lbs even. -with me in it 3030lbs-thats with no passenger seat no rear seats no carpet no center counsil no spare no jack---pretty much nothing left to take out to put off-now the rearend is lighter than the orginal and the engine was a 305 and now is a 350...the specs said it weighed on a site on here 2650lbs-so iv added about 150lbs---if i have a 3030total weight and im guessing my horses are close to 350 and if i can hit 110 in the quarter that would put me in the 11's---i tested it a little on the way to and from the dump were i had it weighed-it scootted good no much burn out did get a second gear scracth-then it started flying...I know i got some if's here so-worst case its in the 12---its a mid 11 to a mid 12second daily driver. I know thats just "Guessing". But mathmatically its there.

 

[63chevystepside]

Anyone know what to do?I have a 350 chevy that was bored 30 over and whoever did it put low compression pistions in it then slaped on 305 heads.---My question is there a way to make 350 heads work with this set up were the pistions are low compression pistions? Without changing pistions and without putting the 305 heads back on---can i shave enough off the heads to make some of it up then put a thinner head gasket on? The manchiest i spoke to said if i just slaped on the heads it would have 8:1 and wouldnt have power and by shaving the heads it wouldnt be enough?---So what you'll think?